# drivingfast.net — full content > The best driving guide on the web — expert articles on car control, racing techniques, track days, off-road driving, road craft and car technology. ====================================================================== # Braking URL: https://www.drivingfast.net/braking/ Category: Car control Question : "How much technique can there be to braking? Surely it's just a matter of stamping on the pedal and coming to a halt?" Answer : Good braking technique is a compromise between the two following factors: If you have locked your front wheels, you lose steering control The point of maximum deceleration is just before the point of wheel lock If you would like to experiment with various different braking techniques, please do it on a track or on private land where nobody will be at risk of being run over. Introducing ABS ABS is a marvellous invention. By rapidly applying and releasing the brakes in pulses when wheel lock is detected, it allows you to both slow down and steer at the same time. All you have to do is hit the brakes hard and watch as you gracefully come to a halt. In cars with ABS many of the techniques listed here will not be relevant (anything that mentions wheels locking), but many racing cars are not equipped with ABS technology so manual braking techniques are still useful for the track. ABS was first introduced in cars in 1978, and the technology now is far more advanced than when initially launched. For many years it was possible to slow down faster using manual braking techniques, and traditionally racing drivers have preferred to brake manually. Conventional racing wisdom tends even to suggest that ABS is not the most efficient method of braking. Today, however, in many real world conditions ABS both prevents wheels from locking and also slows you down quicker than any manual braking technique, especially on wet or slippery roads. What is the fastest method of slowing down in ideal conditions? The following list shows the quickest methods for an experienced driver to slow down in high grip conditions such as a dry racing track. Threshold braking in the wet is much more difficult, and in this case ABS may well be the quickest method. Threshold braking ABS braking Locked wheels Cadence braking Parachute (technique not discussed) Comparing different braking techniques Just because a braking technique is not the quickest to bring you to a halt doesn't mean that it should be avoided - cornering ability while braking also needs to be considered. Locked wheels do not permit steering so this is only an option when you have a clear straight line ahead of you, however ABS equipped cars and the cadence braking technique both allow you to steer at the same time. Which is the best technique for slowing down? This depends on what you are trying to achieve. On the track drivers should usually aim for threshold braking, however even the best drivers in the world occasionally lock up wheels, and it is at this point the decision needs to be made whether to use cadence braking (if ABS isn't fitted), or reattempt threshold braking using slightly less pressure. In general, locked wheel braking should be avoided where possible, as it does not allow steering control to be maintained. Note: In some particularly challenging, low friction braking conditions it can sometimes be beneficial to lock wheels, discussed towards the end of this article. Threshold braking (ABS and non-ABS cars) Threshold braking is the best strategy to adopt to gain maximum braking performance on tarmac. The point of maximum braking performance is found before the point of wheel lock, and when using threshold braking the driver attempts to try and keep the braking pressure just before this point. Practically, it's often very difficult to know exactly the point at which wheels will lock as many factors are at play such as tarmac conditions, tyre choice and brake temperature. Article on threshold braking Brake pressure vs deceleration The graph below explains the science behind threshold braking in a little more depth. The process of locking a wheel does not occur all in one go, and varying amounts of wheel slip can occur until the wheel rotation stops (100% wheel slip). Maximum braking performance occurs at about 20% wheel slip, but as you can see from the graph this only drops about 30% when the wheels are fully locked. So the main points are that the best braking performance in any vehicle occurs before the point of wheel lock, however locked wheel braking is a lot better than nothing. Tyre slip versus braking efficiency So, unless you're a professional racing driver, the best strategy to adopt is to best to brake hard, and if you find some wheels are locking, slightly releasing the brakes and then reapplying with a bit less pressure. As you learn how your car behaves in these conditions you'll get better at judging the pressure needed for maximum deceleration. ABS braking technique If you are the proud owner of a modern sports car, it's likely that the engineers have spend countless hours fine tuning the ABS to provide the best possible performance from the hardware. Modern ABS systems are now so good that unless you're a very good driver it can be hard to slow down more efficiently that by using the system. Even if ABS is fitted and it performs well, it is still better to threshold brake and prevent the system coming into operation in the first place. ABS is reactive and as the old adage goes - prevention is better than cure. Article on ABS technology Locked wheel braking (Non-ABS cars) Ok, so locked wheels aren't quite as good at slowing you down as the threshold braking technique. However there are certain situations when it's very difficult to maintain hard braking without locking wheels, such as on a wet road or track. In this case, sustained wheel lock might not be as bad as you might think. As long as you are heading in the right direction locked wheels will slow you down effectively, but remember that you'll be unable to steer. Which leads us onto the next technique?. Avoidance braking (Non-ABS cars) "So, I'm on an icy road, going too fast (I'm sorry, but it's a bit late for that now!), I've slammed on the brakes, and now I'm hurtling towards a tree!" Well, you've been silly, but all may not be lost. Keep the wheels locked for as long as possible to scrub off speed, and while you're doing this, apply a small amount of steering lock (quarter of a turn is a good starting point). Now, release the brakes smoothly and you should find that steering starts to work again. This may be enough to get you round an obstacle. Keep applying and releasing the brakes at points where it is suitable, using small steering movements, or you'll risk understeer or oversteer. This technique works equally well in good conditions at speed, but really should only be used as an emergency procedure. Cadence braking (Non-ABS cars) Cadence braking is a braking technique for very low grip surfaces such as an icy road - essentially applying and releasing the brakes rhythmically in order to get a compromise between steering and braking performance. As you apply the brakes, the wheels will tend to lock up, slowing the car but preventing you from steering. As you release the brakes you regain steering control and can keep the car pointing in the right direction. Attempting to use cadence braking on a good grip surface at speed will result in weight transfers which can unsettle the car, possibly resulting in oversteer ? the last thing you need when trying to turn a corner. Not a technique to adopt for fast driving on high grip surfaces. Trail braking Trail braking is an advanced technique used when driving on the track in an attempt to improve lap times. We cover trail braking in our track corner section found by clicking on the link below. Trail braking in corners Braking / stopping distances If you go out to learn just one thing about your car, try to get to the point where you instinctively know what the stopping distance will be for different speeds at maximum braking effort. Quoting figures are mostly useless in real life situations, this is something that needs to be a split second decision, not a calculation. The graph above show approximate braking distances in a standard road car in the dry. Source: Green, M. 2000. "How Long Does It Take to Stop?" Methodological Analysis of Driver Perception-Brake Times. Transportation Human Factors 2:3 Braking distances at different speeds Speed Reaction distance Braking distance Total 70 21 75 96 60 18 55 73 50 15 38 53 40 12 24 36 30 9 14 23 20 6 6 12 A real example Ariel Atom 2 300BHP Supercharged 100-0mph = 3.8 seconds = 84.3 meters Source: Autocar Magazine 0-100-0 tests This figure is marked in the graph above in red. As you can see it comes well under trend line for standard cars but this would be expected for a performance car that weighs as much as a small fish. This inconsistency nicely illustrates that fact that you need to get used to the braking performance of your car before you can start to push the limits. Tyre choice Tyres have different breadths of capability. Dedicated slicks are good in the dry, but poor in other conditions. A general purpose tyre will perform well in many different conditions as shown in the graph below. Wet tarmac is less predictable than in the dry, however with the right tyres, good braking performance is possible. Remember to be very careful the first few times you approach a corner to re-calibrate your braking points. Tyre grip levels in different conditions Grip levels for different tyres in different conditions Friction levels for different tyres General purpose tyres Slicks Dry 0.85 1 Wet 0.65 0.5 Heavy rain 0.55 0.4 Puddles 0.5 0.25 Braking in low friction conditions In certain difficult braking conditions, studies have shown it can sometimes be beneficial for wheels to lock in order to aid the slowing of your car. An American study by the National Highway Traffic Safety Administration (NHTSA) found that ABS increased stopping distances on loose gravel by an average of 22 percent. A locked wheel allows a wedge of gravel to build up in front of the tyre, thus aiding braking. A similar issue can occur when driving in snow or in sandy condition, so remember to leave additional room if driving on these surfaces in a car fitted with ABS . ====================================================================== # Grip URL: https://www.drivingfast.net/grip/ Category: Car control Grip is a wonderful thing. It keeps you on the road, it allows you to accelerate, turn corners, and then stop again. However, there is a limit to tyre adhesion and this, sir, is the limit of your car. It's essential to have a grasp of the basic science behind grip if you want to drive on the limit. First, let's think about the contact patch of a tyre - this is the rubber which is actually in contact with the ground at any one time when you're driving along. Contact patch The contact patch This little area of rubber can only supply a finite amount of grip, and for the purpose of explanation this is divided between the front to back (longitudinal) and side to side (lateral) directions. Longitudinal grip is used up when you're accelerating or braking, and lateral grip when you're turning corners and steering. Diagram 2: Contact patch showing the direction of a. longitudinal and b. lateral force Here's the key point - if you are using all the available grip in one direction (e.g. braking), you will not have any available in the other (e.g. steering). Combining lateral and longitudinal forces When first learning to drive fast on the track, it's sensible to perform the most grip-demanding longitudinal and lateral actions separately. For example, when you're accelerating or braking hard on the straight, try to reduce steering inputs to the minimum. Applying this thinking to a corner means braking hard in a straight line, then releasing the brake fully before turning the steering (as shown in Graph 1 below). Performing these actions will reduce the grip demands on the tyres and provides a buffer of reserve grip which can be used should things start to go wrong. Graph 1: Separate braking and steering actions reduce grip demands Professional racing drivers tend to combine some of the lateral and longitudinal driving elements in an effort to extract every last bit of performance from their car. Combining the braking and steering elements of a corner is known as trail braking and it places very high demands on the tyres. Graph 2 shows how the braking and steering forces are added together to provide the total grip demand. In this case, the driver has misjudged the limits of grip and is now sliding out of control (a common mistake). Graph 2: Combining the braking and steering elements of a corner (trail braking) Good drivers know how to get the balance of all these forces right, especially when cornering, accelerating and braking hard. When driving near the limit it's vitally important drive as smoothly as you can, as the slightest driver input (such as a dodgy gear change) can exceed the total grip reserve and leave you heading towards the crash barriers. Learn more about track corners and the racing line here Weight transfers and grip As usual, life is not quite as simple as it first appears, and it may surprise you to learn that the total amount of grip available is not fixed. It in fact depends on a number of factors - one of which is the amount of weight acting on the wheel. If you decrease the amount of weight acting on the contact patch, this artificially lowers the amount of adhesion available, and vice versa. If you're accelerating hard, you will have less grip at the front end, more if you're braking (due to the weight transfers). Photo 1 shows a dramatic sideways weight transfer which has caused the inside rear wheel to lift, leaving no grip available at all. Please see the dedicated article on weight transfers for more information on how traction is affected by driver input. Photo 1: A front engine, front wheel drive car cornering hard Maximising traction The best way of maximising your car's grip is to drive using smooth driving techniques. The way you change gear and use the throttle, brakes and steering can increase or decrease the amount of traction available. The best racing drives are usually the smoothest, and this mantra applies equally well to all driving disciplines. Increasing grip Grip can be increased in a number of ways, all of which are relatively easy to do Grip can be increased in a number of ways, all of which are relatively easy to do. Adding aerodynamic down force such as spoilers, and splitters to a car can increase the amount of available grip by diverting the force of high speed air to your advantage. But beware of cheap spoilers which can be designed as a styling feature only - and if you are planning on fitting an aftermarket spoiler to your car ensure there is enough strength available in the bodywork as some key areas may need reinforcing. Secondly, swapping your standard tyres for more specialist rubber can increase grip in certain conditions. For example, softer compounds usually provide better adhesion on racing circuits, however they usually wear out quicker - it's all a matter of compromise, so pick tyres which best suit your overall usage. Grip and conditions The final point is to remember that your tyre is only 50% of the traction equation when driving, the other 50% is made up of the surface of the ground. Dry tarmac provides dramatically more grip than when wet, and grip even varies between different tarmac types. Ensure you adapt your driving style to suit the conditions, and are constantly aware of the external environment. It's sensible to seek advice from an experienced driver before attempting an unfamiliar circuit for the first time. Let's end with a nice slow motion video of a drag racer's tyre deforming as it accelerates - you can clearly see the fine balance between grip and slip. https://www.youtube.com/embed/h1BlJxvzWIY Now read our article on how weight transfers affect grip ====================================================================== # Heel & toe shifting URL: https://www.drivingfast.net/heel-toe-shifting/ Category: Car control Heel and toe is the art of changing down a gear and rev matching while braking. By combining the braking and gear change when approaching a corner instead of performing them as two separate actions you'll be faster in any driving discipline - an essential skill to master. Before trying heel and toe, might be worth learning about rev matching, which is the precursor skill. Read our related article on rev matching What does heel and toe shifting achieve? Reduces stress on the driveline Prevents forward weight transfers when downshifting Reduces the chances of wheel lock in extreme cases Allows rapid, smooth down changes before entering a corner How do I do it? This technique is possible by turning your right foot inwards, using your toes to operate the brakes and your heel to increase the throttle. Although this sounds complicated, it's actually a relatively easy technique to master with a bit of practice. The technique is vital on the track, but will also make you a much smoother driver on the road. Video Here's a video showing the technique Heel and toe, step by step: Step 1 Heel and toe is mostly used to change down in anticipation of a corner. Diagram 1 (below) shows a driver accelerating in third gear, approaching the top of the power band with the road speed increasing. Diagram 1: Accelerating in third gear As you approach the braking point of a corner, cover the brake pedal with the ball of your right foot. The brake is the priority of the two pedals, so ensure good contact and no risk of your foot slipping off. In some cars it is very difficult to heel and toe due to the pedal position. It's useful to wear racing boots or thin soled shoes to increase your pedal feel and decrease chances of your foot sliding off the brake. Step 2 When you reach the braking point, press the brake pedal and reduce your road speed to a point where it's possible to change down without over-revving the engine (see Diagram 2 below). In this example, the driver is in third gear, reducing speed before a shift into second. Diagram 2: Braking hard before a corner, engine speed decreases as road speed drops Step 3 When it's possible to change down and while still braking, rotate your right foot and prepare to press the accelerator with your heel. Alternatively if your pedals are close together it may be possible to use the side of your foot. At the same time, press the clutch with your left foot to disengage the wheels from the engine. Diagram 3: Rotating the right foot in preparation to press the throttle, pressing clutch Step 4 Once the clutch has been pressed, engine speed will start to drop rapidly. Increase the engine speed using the throttle with the heel of your right foot in order to match the revs in second gear to the road speed. You will have already mastered rev matching, so this should be an easy job now. Diagram 4: Pressing the throttle with the heel to raise engine speed Step 5 When the road speed and the engine speed match, select the gear which will allow you to exit the corner quickly, in this case second (shown in Diagram 5). This step is done very fluidly with Step 4. Diagram 5: Changing to second gear Step 6 Come off the brake, smoothly and progressively release the clutch. Tackle the corner then accelerate smoothly and prepare for the next bend. Diagram 6: Release the clutch, and accelerate out of the turn Congratulations, you've just successfully shifted using heel and toe. But practice makes perfect - use this technique every day until it becomes second nature and you'll start to shave seconds off your lap time. ====================================================================== # Left foot braking URL: https://www.drivingfast.net/left-foot-braking/ Category: Car control Left foot braking is a technique used frequently in rallying, but can be equally useful on the road or track for the following: Reducing understeer into a corner Reducing drive loss through spinning wheels Removing the pedal transfer time between accelerator and brake Left foot braking Reducing understeer into a corner The theory here is that you can feather the brakes into a corner (trail braking), while transitioning to progressive throttle at the apex. This can lead to a very smooth transition between braking and acceleration and is less likely to unsettle the car through unwanted weight transfer. It also keeps the weight at the front of the vehicle for as long as possible, thus providing more grip, a better turn in and reduces the possibility of understeer. Reducing drive loss through spinning wheels This technique is particularly useful for a front wheel drive car without a limited slip differential. On the exit of the corner, it is a common symptom for one the unladen front wheel to spin while applying throttle. This spinning wheel is preventing all of the power from transferring to the road and thus slowing the exit speed. By feathering the brake with the left foot, this can prevent or reduce this wheelspin, and get a better exit. Removing pedal transfer time Using the left foot to brake removes the pedal transition time from brake to accelerator and vice versa. This can shave fractions of a second off a lap time when done well, but cannot be used when it is necessary to change down a gear (unless you decide not to use the clutch!) Common mistake Left foot braking is an advanced technique, and should only be attempted after lots of practice. When learning to left foot brake, you'll initially press the pedal far too hard as you'll be used to the action of pressing a clutch all the way to the floor. It takes time to re-programme the 'muscle memory' of your foot and leg, and a bit of empty tarmac is highly recommended. ====================================================================== # Oversteer URL: https://www.drivingfast.net/oversteer/ Category: Car control Oversteer is related to understeer and occurs when the rear tyres reach the limit of adhesion in a corner before the front while cornering. This leads to 'the back coming out'. If you manage to perform sustained, controlled oversteer this is know as drifting. Read about drifting Read about understeer Oversteer overview The diagram below shows the path that that is travelled during an episode of oversteer. Stages of oversteer in a corner A. The car has turned in normally and is aiming towards the apex. B. The rear wheels have started to lose adhesion, the driver compensates by steering left to keep steering aligned to the desired driving line (counter steering, explained below). C. The driver has maintained control of the car and continues to follow the desired line. D. The car is at the limit of left hand lock, a spin is likely at this stage unless dramatic corrections are made. Close up of stage C Oversteer is more exciting than understeer and like most exciting things (such as jumping off cliffs) there is an element of risk involved. Most 'driver's cars' have a tendency to oversteer when on the limit around corners, and this property can be found in a variety of vehicle layouts and drive formats. Oversteer - factors involved Oversteer results from a number of factors, some of which involve the natural handling characteristics of the car, and some result from the way it's being driven. Passive factors at work (the natural properties of the car) Weight distribution (front or rear bias) Engine and drive layout Suspension & chassis setup Tyre type, wear and pressures Active factors involved (the way it's being driven) Cornering speed Throttle Braking Steering inputs Weight transfer Symptoms It's unlikely you'll ever experience oversteer unless you're driving a car near the limits of grip. You can recognise oversteer if... The rear of the vehicle becomes unstable and 'light' due to lack of grip. The car starts to rotate so the driver is facing towards the inside of the corner. Causes There are four major active causes of oversteer, but what you're likely to encounter depends on the car being driven (for more information on this please skip to the next section). Causes include: Entering the corner too fast Accelerating into the corner, too early or too aggressively Braking into the corner or mid corner Lifting off the throttle mid-corner. This scenario is also known as: lift-off oversteer snap-oversteer trailing-throttle oversteer throttle off oversteer lift-throttle oversteer Lift-off oversteer Lift-off oversteer is a phenomenon which can occur when reducing the throttle mid corner. This will only happen when driving close to the limit so only experiment when on the track! Sporty front wheel drive drive cars can be especially prone to this due to the heavy front end and light rear. Reducing the throttle input results in a forward weight transfer, which increases the grip at the front tyres, but reduces levels at the rear. If this is performed during cornering, the combination of the heavy front end and the reduction of grip can cause the rear wheels to break traction and start to slide towards the outside of the corner. In the image below, the driver of a front engine car lifts off the throttle mid corner at [A] which results in lift-off oversteer at [B] due to a forward weight transfer. Lift-off oversteer Luckily, lift off oversteer can usually be corrected by reapplying the throttle and accelerating. This should pull the front of the car forwards and straighten out the car, but continuing to reduce throttle application can cause the car to spin. Steering in the direction of the intended direction of travel will help keep the car on track. Oversteer and racing / performance cars Most performance cars have a tendency to oversteer as they are usually developed to provide a large amount of grip at the front wheels (to turn into corners well at speed), and a large amount of power (usually at the rear wheels). This means that if traction is lost it will usually be at the back first. Thus in most cases the ideal cornering technique in a performance car needs to try and reduce or control oversteer. Preventing & correcting oversteer - rules of thumb To correct any form of traction loss, you need to consider why you've exceeded the limits of grip at the wheels. In all cases of oversteer, counter steering is also required. 1. Entering the corner too fast Enter a corner too fast and you're asking for trouble. Unless of course you have a lovely long run off to play with or if you're driving Silverstone in a go-kart. It's not the quickest way to take a corner and leads to increased risk of oversteer. If you have entered a corner too fast, ensure that every input you make is incredibly smooth, and take the easiest route. Next time make sure your entry speed is slow enough to maintain grip, you can build up speed as you gain experience. 2. Accelerating into the corner, too early or too aggressively If you manage to break traction at the back when applying throttle, you're probably in a powerful car and need to be less aggressive. If you're spinning wheels, the power is not transferring to the road and you're not benefiting from the many horses you have sitting under the bonnet. Gently ease off the gas and you should regain adhesion at the rear wheels. 3. Lifting off the throttle mid-corner If you are on the power mid-corner and close to the limit, do not lift off the throttle. The resulting forward weight transfer can upset the balance of the car and allow the rear wheels to break loose. In a front wheel drive car, reapplying the throttle can often help in this situation. 4. Braking into the corner or mid corner You should avoid braking in corners in most situations, however there are circumstances which require the use of the anchors. Ensure braking inputs are especially smooth, gentle and progressive, and if a squirrel has just run out in front of you, try steering around rather then doing an emergency stop. To correct brake-induced oversteer, smoothly (but rapidly) release the brake and adhesion should be reintroduced. Correcting oversteer - counter steering / opposite lock Whatever the cause of oversteer it is important to keep the front wheels pointing in the direction you're hoping to go. If you fail to do this, the most likely result is a spin. This technique is known as counter-steering or applying opposite lock (see Diagram 3). You should apply enough steering lock to point the wheels in the direction of the slide as shown below. Too little and you're likely to spin as the back continues to come round, too much and the car will rapidly over-correct, often resulting in a spin in the opposite direction. The skill can only be mastered with plenty of practice and should become instinct if you're planning to drive fast on a track. Tip: Always look and focus on the direction you're hoping to go - this makes the steering correction almost automatic. Conversely - don't concentrate too hard on that tree you're hoping to miss as you will be more likely to head in that direction. Counter-steering, applying opposite lock Applying corrective steering needs to be done rapidly to catch the back of the car before it slides to a point which may be difficult to control. Once the slide has been controlled and the back starts to fall back in line, it's also important to get the steering correction off quickly too, otherwise you might find yourself with oversteer in the opposite direction due to the resulting pendulum effect. Oversteer and different drive / engine layouts Rear wheel drive In a rear wheel drive car you have the benefit of sharing the demands on adhesion between the front and rear wheels. The front wheels do the steering and the rear do the accelerating (and deceleration under engine braking). This usually results in a more balanced vehicle. In most conventional front engine, front wheel drive vehicles such as the Ford Fiesta it is rare to ever experience anything other than understeer. Rear wheel drive cars can experience oversteer for different reasons depending on where the engine is located. Rear wheel drive, front engine [e.g. BMW M3, Mazda MX5] Front engine, rear wheel drive Causes, and likelihood of oversteer for a real wheel drive, front engine car Cause of oversteer Likelihood of oversteer Entering the corner too fast High Accelerating early or aggressively High Lifting off the throttle Medium Braking Medium In a front engine car, most of the weight is over the front wheels. This usually results in higher natural levels of grip at the front (which is useful for steering and braking). The comparatively unladen rear wheels may have lower natural levels of grip, which can lead to oversteer especially when accelerating round a corner. This is the reason some very high powered cars have wider wheels and tyres at the back. Question : When a front-engine rear-wheel drive car accelerates hard in a corner, there is a high possibility of oversteer. I also understand that weight is transferred to the rear under acceleration, therefore i would like to know how the rear wheels can still lose traction when weight is transferred to the rear and on to the rear wheels. Answer : There are many factors at work when cornering and it's a fine balance of forces. It's important to understand that when you're cornering there is much less grip available for acceleration and braking. For a rear weight transfer to occur in the first place, you need to have the grip available to put the power down - if you try to accelerate hard you're likely to overwhelm the rear tyres and spin one or both of the wheels. This reduces the physical grip dramatically which can then lead to oversteer. Rear wheel drive, rear engine [e.g. Porsche 911] Rear engine, rear wheel drive Causes, and likelihood of oversteer for a rear wheel drive, rear engine car Cause of oversteer Likelihood of oversteer Entering the corner too fast High Accelerating early or aggressively Medium Lifting off the throttle High Braking High Rear engine, rear wheel drive vehicles such as the Porsche 911 can oversteer for different reasons to front engine varieties. In this case most of the vehicle weight is over the rear wheels, leading to greater levels of natural grip at the back, which should lead to an inherent low risk of oversteer. However, there is another force at work here - momentum. Objects with greater mass carry more momentum and are harder to change direction at speed. In the case of rear engine cars, the rear has more momentum than the front which can lead to a greater risk of oversteer as a result of braking or lifting off mid corner. Mid engine cars can also oversteer for similar reasons, but tend to provide a better balance of under and oversteer. Front wheel drive (front engine) [e.g. Peugeot 205 GTi, Renault Clio Cup] Front engine, front wheel drive Causes, and likelihood of oversteer for a front wheel drive car Cause of oversteer Likelihood of oversteer Entering the corner too fast More likely to understeer initially Accelerating early or aggressively Low Lifting off the throttle High Braking High Sporty front wheel drive cars are more likely to experience oversteer than a standard car due to the vehicle setup. Dial out the inherent understeer tendencies of a front wheel drive car using clever engineering, and the result is a better 'turn in' and an increased ability to oversteer due to the naturally light rear. In this case, it is usually possible to accelerate out of the oversteer situation, using the rearward weight transfer to actively increase levels of grip at the back. Front wheel drive cars are especially prone to lift off oversteer due to the forward weight transfer combined with light rear end. Question : When a FWD car accelerates, weight is transferred to the rear. Does this mean that the front of the car where the engine is located becomes lighter than the rear during acceleration? Answer : Firstly, the weight transfers which result from acceleration are perhaps not as great as you think. This is because you're unlikely to be able to accelerate as quickly as you can brake or change direction with the steering - thus the advantages or rear weight transfers are usually slightly less than in other directions. It's very unlikely any front engine car could accelerate to the point that the rear weights more than the front. There will be some transfer of weight onto the rear wheels, but not that much. Four wheel drive [e.g. Subaru Impreza, Nissan Skyline, Audi Quattro] Four wheel drive, front engine Causes, and likelihood of oversteer for a four wheel drive car Cause of oversteer Likelihood of oversteer Entering the corner too fast Medium Accelerating early or aggressively Medium / High Lifting off the throttle Medium Braking Medium Four wheel drive vehicles can oversteer as much as rear wheel drive cars, depending on setup. However, due to the sharing of drive forces over all four wheels, there is less risk of oversteer due to too over-exuberance with the throttle pedal. Treat as a rear wheel drive vehicle and you won't go far wrong. With particularly powerful four wheel drive vehicles it may be possible to enter a 'four wheel drift'. This is a particularly spectacular way of exiting the road! Simple modifications to make a car less prone to oversteer If you have a track car and find oversteer a problem, you can complete some relatively easy modifications which can make the handling more neutral. These include: Reducing the rear tyre pressure Softening rear springs or anti-roll bar Use softer rear tyres Increase rear down-force (if aerodynamics fitted) If you want to try something a little more daring, the chart below can help. Advanced oversteer diagnosis and modifications Below is a flowchart which can help diagnose and treat the symptoms of oversteer. Oversteer diagnosis Disclaimer: Always stick to the manufacturer's recommended limits when altering tyre pressures, and never modify a road car. ====================================================================== # Rev matching URL: https://www.drivingfast.net/rev-matching/ Category: Car control Rev matching is used when down-shifting to smooth the transition between gears, and prevent shock loads through the transmission. It's a useful skill for the road and track for both cars and motorcycles. Read our dedicated article on motorcycle rev matching Introduction Each gear has an effective operating range of speeds which depend on the rev range of the engine. The faster the engine rotates, the quicker you can go up to the point when you need to change up a gear. Within the operational rotational speeds of the engine, there is a range of optimum efficiency known as the 'power band', and this is where the fastest acceleration can be obtained (see Diagram 1). Diagram 1: The power band of an engine in any particular gear Most gearboxes are designed so that when you change up a gear when accelerating, the next gear will be at or near the start of the engine's power band (see Diagram 2). This design provides maximum acceleration all the way up to the top speed of the car. Diagram 2: Comparing the power bands in two gears At most speeds, a selection of gears can be used (see Diagram 3). Diagram 3: Gear choice at different speeds In the illustration above the driver could choose second, third or forth gear. In second gear the engine speed would be at the top of the power band, not leaving room for much useful acceleration until the rev limiter is activated. In forth the revs would be too low, leading to sluggish performance (but perhaps decent fuel economy). In third gear the engine would be at start of the power band providing maximum acceleration this would be the choice of the performance driver. Changing up / up-shifting Lower gears provide greater acceleration due to the mechanical advantage of the gearing and the higher engine speeds. Therefore, when accelerating hold on the lower gears for as long as you can, but be careful not to hit the rev limiter as this only slows you down. Only change up when the engine has passed through the upper limits of the power band, not before. Changing down / down-shifting When approaching a corner, you need to select a gear which will provide maximum acceleration at the exit , and this gear needs to be engaged before entering the corner. This means braking to the speed where you can safely turn into the bend, then shifting before turning in. Ideally you'll need to select a gear which will cause the engine speed to increase to a sensible point within the power band so that plenty of power is available when accelerating out of the turn for that quick exit. However if you select the correct gear and let out the clutch swiftly, three things will happen: Significant levels of engine braking will occur In extreme cases, the wheels can lock up (image selecting second gear at 80 mph and dumping the clutch) A forward weight transfer will occur None of these are good when you're trying to maintain control of a car driving near the limits of grip. Rev matching is the solution to these potential issues. Introduction to rev matching Rev matching is a technique which should be second nature if you want to be quick on the track and smooth on the road. When is it used? When changing down to create smooth, fast gear changes in a car with synchromesh. Almost all modern cars have synchromesh, if you don't have it fitted you will need to 'double de-clutch' (you'll know). What rev matching does: Reduces stress on the drive-line Prevents forward weight transfers when down shifting Reduces engine braking and chances of wheel lock Note: On the track, the general rule is to use the brakes to slow down and the engine to accelerate. Engine braking is not efficient, and will not slow you down quickly enough for track use. If you have time to use engine braking, you're not going as quickly as you could. How to rev match when changing down: 1. Rev matching is mostly used to change down in anticipation of a corner. Diagram 4 (below) illustrates a driver accelerating in third gear, approaching the top of the power band. Diagram 4: Accelerating down a straight in third gear 2. As you approach a corner, brake until you have reached a safe speed to turn into the bend - engine speed will drop as road speed decreases. In Diagram 5 below the driver is in still in third gear, but is planning to select second for a quick exit. The engine speed has now dropped to the point where a change to second would be possible. Diagram 5: Braking before a corner 3 . While still on the straight, press the clutch in order to change down. This disengages the engine from the wheels and thus the engine speed starts to drop quickly. The desired gear is second, but Diagram 6 shows that at the current road speed, the engine revs will need to increase in order to mesh smoothly when releasing the clutch. Diagram 6: Pressing the clutch in preparation to change down 4. Select a gear which will provide decent acceleration at the exit of the corner, in Diagram 7 the driver has selected second gear. Simultaneously use the throttle to increase the engine speed in order to match the revs in second gear to the road speed. Diagram 7: Select second gear and apply throttle until the revs match 5. When you think the revs are at a suitable speed, release the clutch smoothly and progressively then turn in and start to accelerate out of the corner. If done well, there should be no jolt as the clutch is released (Diagram 8). Diagram 8: Second gear is selected, engine revs match road speed and the clutch is let out. 6. Congratulations, you've learnt to rev match! You don't need to be 100% accurate when raising the engine revs, and you'll improve dramatically with practice - try to make this a technique you use every time you drive. With time, you'll instinctively know when the revs match the road speed and be able to rev match with a satisfying and rapid blip to the throttle. Now you're ready to learn heel and toe shifting, which is rev matching while on the brakes. Learn about heel and toe shifting ====================================================================== # Smooth driving URL: https://www.drivingfast.net/smooth-driving/ Category: Car control In every discipline from drifting to racing, aggression does not equal speed. If you only learn one skill to improve your driving technique it should be the art of smooth driving. On the track, driving smoothly allows you to minimise weight transfers, make the most of every last bit of grip, and maintain control at higher speeds. On the road it makes the drive more comfortable for your passengers and can even increase fuel economy. Remember, if you're driving at only 50% of the car's potential, you'll be able to get away with changing gear roughly and braking, accelerating and steering aggressively. But when you're driving near your car's limits these actions can lead to loss of traction, poor track times and increased risk of an accident. It's important to get into good habits even if you're not travelling at breakneck speeds. Steering Shuffling your hands is not a smooth technique When driving on the track, hold the steering wheel at the ten to three position (Diagram 1) to allow fairly tight radius corners to be tackled without having to take your hands off the wheel. If your car requires a large number of turns from lock to lock you should reposition your hands on the wheel accordingly before taking a tight bend. Shuffling your hands is not a smooth technique. Dedicated article on steering technique Diagram 1: Correct steering position for maximum smoothness Graph 1 below plots the grip demands on the two front tyres which result from turning a simple corner (ignoring other forces). In this case, the driver does not approach the limits of grip at any point as a result of steering. When turning a corner, there is usually a spike in force as the weight transfers to the outside of the car, and it's at this point loss of traction is most likely to occur. Grip demands then remain relatively constant for the duration of the corner, then reduce as the steering lock is unwound. Once the car is straight, there is usually an additional small spike in force as the weight transfers to the opposite side (this is known as the pendulum effect). Graph 1: Demands on grip when cornering when steering smoothly The lessons to take from the graph are as follows: Avoid 'chucking' the car into a corner - ease it in, allowing the weight to shift to the outside of the car in a progressive manner. Spikes in force need to be avoided when driving near the limit. Do not place additional demands on grip early in the corner (i.e. by braking or accelerating hard), as this is when loss of control is most likely. Unwinding the steering in an aggressive manner is just as likely to upset the balance of the car ? all steering motions should be smooth. Braking Squeeze the brake pedal smoothly You can brake much faster than you can accelerate so the forces involved have greater potential to unsettle the balance of your car and cause loss of traction. Squeeze the brake pedal smoothly, never stamp on the brakes, and try not to get into the habit of allowing ABS to sort out locked wheels. This doesn't mean that you can't press the pedal hard, but ensure that the pressing and releasing motions are progressive. This will keep weight transfer spikes to a minimum and reduce the chances of unnecessary weight transfers or wheel-lock. Dedicated article on braking technique Graph 2 below shows the grip demands placed on the tyres by braking smoothly, yet relatively hard. There tends to be an early peak of force as the weight transfers forward (which is when wheel-lock is most likely to occur). Brake application should be tapered at the start and finish to avoids spikes on the graph. Graph 2: Demands on grip created by braking Acceleration Smooth, progressive accelerator inputs are more important in more powerful cars as there is a greater likelihood of wheel-spin. Never stamp on the gas in a powerful car when accelerating or after a gear change - this can lead to spinning wheels and loss of control. In addition, remember that engine braking can just as important as acceleration, so think about weight transfers in mind when lifting off. Lift-off oversteer can result if you come off the gas mid-way through a corner. Dedicate article on getting a quick start Graph 3 plots the grip demands on the driven wheels while accelerating smoothly from stationary. As you can see, the largest demands on grip occur as the clutch is released, revs are high and the car is pulling away. The graph also shows the spike in force as the driver lifts off the gas and engine braking kicks in. Graph 3: Smoothly accelerating from stationary - grip demands on the driven wheels Graph 4 shows an aggressive driver pulling away with high revs and 'dumping the clutch'. This driver has exceeded the maximum amount of grip available and wheel-spin has now occurred. The driver continues to use high revs, which in this case causes 'fishtailing' as the rear wheels fight for grip. This is not a good way of getting a quick start. Graph 4: Accelerating hard, spinning wheels in a rear wheel drive car Changing gear Avoiding shock loads through the transmission is essential When changing up or down, avoiding shock loads through the transmission is essential, especially in a powerful car. When changing down, releasing the clutch rapidly can result in rapid forward weight transfers and in extreme cases, the driven wheels can lock. Use rev matching (discussed later) where possible to smooth out down changes, and release the clutch with mechanical sympathy in mind. When changing up, releasing the clutch smoothly and moderating the use of the throttle is essential to prevent wheel-spin (especially important in a powerful car). Remember that a missed gear due to a rushed gear change is much worse than taking a little more care with the shifts. Never change gear mid-corner if it can be avoided, and when approaching a bend ensure you prepare by selecting a gear which will allow you to accelerate out. Diagram 2: A smooth gear shift is vital to get the best times on the track Weight transfers It's important to keep unwanted weight transfers to a minimum when driving close to the limits of grip. Rapid weight transfers caused by aggressive steering, acceleration, braking or gear changes can upset the balance of the car, and potentially cause you to lose control. Conversely, weight transfers can also work in your favour. For example, lifting off the throttle briefly before entering a corner may increase the available grip at the front wheels, lead to a better turn in, and reduce understeer. Dedicated article on weight transfers Diagram 3: Large weight transfers can be produced by aggressive steering Rev matching Rev matching is a technique used to prevent weight transfer when changing down Rev matching is a technique used to prevent unnecessary weight transfer during down-changes in a manual transmission car. For a demonstration of why this concept is useful, select third gear and accelerate to about 3000rpm, then quickly select second and release the clutch fairly rapidly. You'll notice a large forward weight transfer as the engine speed is forced to increase. This can also cause the driving wheels to lock in extreme situations. Rev matching will make you a much smoother driver when changing down through the gears, a skill which is useful for the track and can lead to faster lap times. This technique is performed by depressing the clutch, selecting the required lower gear, increasing the throttle, and then releasing the clutch smoothly. You'll need more revs if changing from forth to second that from fourth to third. With practice, this can result in very rapid and very smooth changes, and is almost essential if driving on the track. Rev matching can also be performed while braking, this is known as heel and toe. When you first start to learn this technique, you might find it hard to predict the amount of revs you'll need for each gear, but remember any increase in revs is better than none. Dedicated article on rev matching Combining acceleration, braking, and steering Smooth driving is most important when driving near the limits of your car. When you're taking a tight corner at high speed, the slightest press of the brake or accelerator pedal is likely to result in loss of traction. Graphs 5 and 6 consider the grip demands on a car during the process of cornering on the track. In Graph 5, the driver has separated out the acceleration, braking and steering elements of the corner, which won't yield the best lap times but will increase safety. Graph 5: When cornering, separate driver inputs reduces chances of traction loss Graph 6 shows a driver who is combining steering with both the braking and acceleration elements of the corner in an attempt to gain better lap times. Steering while braking into a corner is known as trail braking and is an advanced technique, however accelerating at the latter stages of the corner is more commonly used. Great care should be taken when performing these actions, as the combined demands of the lateral and longitudinal forces on the tyres is much more likely to exceed the limits of grip (the yellow dots below). Learn more about the science of grip here Graph 6: Combined actions when cornering lead to faster lap times, but greater risk of loss of control ====================================================================== # Steering URL: https://www.drivingfast.net/steering/ Category: Car control Good steering technique is crucial for smooth driving, as it prevents any sudden lateral weight transfers which allows the corner to be taken at a higher speed. Driving position When getting ready for the track you should adjust your seat to a much more upright position than you may use when driving on the road. You should be able to rest your wrists comfortably on the top of the steering wheel while keeping a slight bend in your arms. This may mean moving closer to the wheel than you normally would which can feel strange at first, but will give you maximum control. Click here for more information on driving position for the track Hand position When driving on a stretch of straight or gently curving tarmac, the default hand position is quarter to three (Figure 1). When taking tighter corners it will be necessary to adjust hand position accordingly. Grip the wheel with a firm but relaxed grip, but not so hard that your knuckles turn white! Try to maintain this position unless it isn't possible to take the corner in this way, as this gives you the advantage of instantly knowing exactly where the straight ahead position is, and the ability to steer rapidly yet smoothly. Figure 1: Default steering position For a tight right hand hairpin, a suggested hand position is shown in Figure 2. This will allow the lock to be applied and taken off without either taking hands off the wheel or adjusting the hand position until after the corner has completed. If your car has a large number of turns from lock to lock, you may need to start with your right hand further anti-clockwise. Figure 2: Hand positions for a tight right hand corner Steering for a right hand corner Steering movements The ideal steering movement is progressive, smooth and controlled When steering round a corner, the ideal steering movement is progressive, smooth and controlled. Applying and taking off steering lock should be done in a fluid movement, without taking either hand off the wheel where possible. 'Pushing and pulling' the wheel may be fine for general road driving, but this does not allow the smooth motions needed when driving near the limits of grip. Try not to let the steering wheel slide through your fingers when letting off steering lock, and then adjust your hand position accordingly for the next corner or straight. In some situations when you need to take the lock off very quickly - you may find it easier to let the wheel slide through your fingers slightly, but this should be avoided where possible. An example could be when letting off the steering lock after a dramatic oversteer correction. Steering through a corner When taking a corner, aim for the apex and turn in a smooth controlled arc - don't use aggressive steering unless you're deliberately trying to unsettle the car (e.g. for a handbrake turn). Once you've clipped the apex, unwind the steering lock progressively as you increase the throttle. If you find you have to tighten up mid-corner you've hit the apex too early, and if you find you don't need to use the entire width of the track on the exit you've probably left your cornering too late. ====================================================================== # Understeer URL: https://www.drivingfast.net/understeer/ Category: Car control Understeer occurs when traction is lost at the front wheels while cornering, forcing you wide on a bend despite applying the correct steering angle (Diagram 1). When viewed by an observer, this action looks as if the driver has applied insufficient steering lock (or under steered). If you're car is understeering, you're scrubbing off speed and missing the optimum line, so it's not a quick way to take a bend. Overview The stages of understeer A. The car has turned in towards the apex B. The driver has hit the apex but has found the car is pushing wide of the desired line (dotted) C . Despite increasing the steering angle, the car has taken a line which is not tight enough to take the turn D. The car has been forced off the track by understeer Close up view of understeer Understeer is most likely to result from the following scenarios (which are more difficult to correct as you move down the list): Accelerating into a bend Braking into a corner Ploughing into a corner too fast Low traction conditions on the corner such as ice or oil Having lost traction, understeer is actually a fairly stable state for the car to be in, and thus many manufacturers 'engineer in' this behaviour. Understeer - factors at work Passive factors involved Weight distribution Drive layout Suspension & chassis setup Tyre type, wear and pressures Active factors involved Cornering speed Throttle Braking Steering inputs Weight transfer Symptoms of understeer Light steering Drifting towards the outside of a bend Possible tyre noise from the front wheels Correcting understeer To correct any form of traction loss, you need to consider why you've exceeded the limits of grip at the front wheels... Article on traction and grip 1. Accelerating through a bend Picture the scene, you're in a front wheel drive car on a roundabout about to take the third exit but you think it might be a laugh to go round again. You keep accelerating through the bend and find that the car has a tendency to run wider and wider. The available grip at the front wheels is being used in equal amounts to accelerate and to steer. As you accelerate more, you have less grip to steer - simple. So, reducing either of these inputs will correct the understeer. This is the easiest form of understeer to correct, and a slight, smooth reduction in power will free up more grip (with the added benefit of a forward weight transfer), and a small corrective input to the steering will get you back on line. In a rear wheel drive car, in theory the front wheels will be able to resist understeer for longer due to the division of steering and drive between the front and back wheels. However, understeer can also be engineered into a car for safety, and most rear wheel drive cars will also understeer if power is progressively applied mid corner. If you do decide to accelerate aggressively mid corner you're likely to cause oversteer. Click here to learn about oversteer 2. Braking into a corner When you apply the brakes, most of the braking effort is exerted on the front wheels due to the forward weight transfer. So if you're braking into the corner you're already using most of your available grip trying to scrub off speed. If you then apply some steering lock, the addition of these lateral forces on the tyre can cause the limits of grip to be exceeded. So, correcting understeer seems simple - stop trying to turn the corner (a better plan might be to get your braking out of the way while you're in a straight line). However, if you happen to be in the middle of a bend as your car starts to understeer, continuing straight on might not seem like the best plan. An alternative strategy could be to reduce your braking effort, freeing up more grip for steering and hopefully allowing you to take the bend successfully. 3. Ploughing into a corner too fast If you have attempted to take a corner too fast, have turned the steering wheel, and find yourself running wide, you my friend are in a spot of bother. But before you close your eyes and hope for the best, all may not be lost. You've exceeded all of the available grip, yes, but it may be possible to actually increase the level of grip by the slightest, smoothest dab on the brakes. "The brakes?!", I hear you shout, "but surely that is adding to the demands of the tyres, not reducing them?". This is very true, but if you're not totally out of control by pressing the brakes you're causing the weight to transfer to the front, and thus artificially increasing the levels of adhesion at the wheels. This may, however, not work. The moral is to enter the corner at a slower speed, then get on the power early on the way out. 4. Low traction conditions If you've entered a corner at speed and notice a sudden reduction in traction due to oil, black ice or a banana skin, the best course of action (in the immortal words of Douglas Adams) is to consider how lucky you are that life has been kind to you so far. If life hasn't been kind to you, consider how lucky you are that it won't be bothering you much longer. Alternatively, be careful, think about the conditions and adjust your entry speed accordingly. Avoiding understeer - rules of thumb Be as smooth as you can Don't enter corners flat out, and accelerate as you exit Don't brake in a corner. The only exception to this is if you are using trail braking... Trail braking In some situations on the track, it may be possible to get a better time by leaving your braking to the very last minute, forcing you to maintain braking into the turn. If this is the case, ensure most of the braking effort has been carried out in a straight line, and progressively release the brakes as you approach the apex. The resulting forward weight transfer can reduce understeer and improve 'turn in', however, it can also make the car more prone to oversteer. This is an advanced technique and should only be used once you are very confident with your car, the track and the conditions. To read more about trail braking, click here Simple modifications to make a car less prone to understeer If you have a track car and find understeer a problem, you can complete some relatively easy modifications which can make the handling more neutral. These include: Reducing the front tyre pressure Softening front springs or anti-roll bar Use softer front tyres Increase front downforce (if aerodynamics fitted) Might be worth consulting an expert before doing anything too dramatic, but if you're feeling adventurous, the chart below can help. Advanced understeer diagnosis and modifications Below is a flowchart which can help diagnose and treat the symptoms of understeer. Understeer diagnosis Credit to 'Competition Car Suspension' by Greg Simmons for the original image Disclaimer: Always stick to the manufacturer's recommended limits when altering tyre pressures, and never modify a road car. ====================================================================== # Weight transfers URL: https://www.drivingfast.net/weight-transfers/ Category: Car control There are three ways that weight transfers can occur: Acceleration Deceleration Steering Why do weight transfers occur? Weight transfers occur as a result of the chassis twisting around the car's roll centre, which determined by the natural suspension setup. When accelerating, braking or steering, the body of the car rotates in the opposite direction, which compresses the suspension on one side of the car, while releasing the weight on the other side. Figure 1: Forces causing rotation of the chassis around the roll centre Acceleration - rear weight transfer When you accelerate, the weight of the car is thrown backwards (see Figure 2). This causes the rear suspension to compress slightly and increases the available grip at the rear tyres. See our grip section for more information Figure 2 - Rear weight transfer due to acceleration Advantages of rear weight transfer 1. Pulling away in a rear wheel drive car If you're trying to get a good start, rear weight transfer can play to your advantage in a rear wheel drive car, as the resulting increase in grip will provide you with more traction and reduce any wheel-spin. In a front wheel drive car, however, you're more likely to get wheel-spin off the start, so an extra smooth throttle application is important. 2. Preventing oversteer in a front wheel drive car Oversteer is caused by a lack of traction at the rear wheels, but if you accelerate in a front wheel drive car as oversteer is occurring, the resulting rear weight transfer can increase the available grip at the rear wheels and aid recovery. Note: Oversteer in a rear wheel drive car is rarely helped by acceleration, as this will increase the traction demands of the rear wheels, and leave less available grip to oppose the sideways motion. Disadvantage of rear weight transfer Can cause understeer Understeer results from a lack of traction at the front wheels. If you're accelerating into a corner, the levels of grip at the front wheels will be reduced due to the rear weight transfer, and be more prone to continuing in a straight line despite your steering inputs. Deceleration - forward weight transfer Cars can brake much harder than they can accelerate. Weight transfers under braking are thus more likely to affect the balance of the car (see Figure 3). Figure 3 - Forwards weight transfer due to braking Advantage of forward weight transfer Prevention of understeer If you're hurtling towards a corner, turn the wheel and find yourself ploughing straight on, you've probably approached too quickly. But all might not be lost - easing off the throttle will result in a forwards weight transfer which will increase the available grip at the front wheels. Hopefully this should correct your course. If you're already off the gas, then a light dab on the brakes should help. Disadvantage of forward weight transfer Reduction of traction at the rear wheels If you stamp rapidly on the brakes, you'll find that the rear wheels (in a car without any clever technology) will tend to lock up first. This is the reason almost all cars have smaller brakes at the rear. Despite this fact, the rear wheels are still the most likely to lock when using the brakes aggressively. Braking in a corner should be avoided for the same reason, as this can result in oversteer. Transitions in weight transfer To get the best times on the track you need to be either accelerating or braking hard on the straights - any coasting means you're not going as fast as you could. When transitioning between accelerator and brake you'll get exaggerated weight transfers which can further upset the balance of the car. Steering Figure 4: Weight transfer as a result of steering It's important to consider sideways weight transfers when cornering. If you turn into a corner progressively rather than 'chucking it in', this will transfer the weight to the outside wheels in a gradual manner. As the outside wheels provide most of the cornering effort, the resulting progressive increase in grip can help you take corners at a greater speed before traction is lost. However, if you throw the car into a corner, the sudden weight transfer can unsettle the vehicle and cause the wheels to break traction suddenly. The moral again ladies and gentlemen is smoothness . An example Take a front engined rear wheel drive car as an example and throw it into a corner hard while accelerating gently. Diagram 4 below shows the levels of grip at each wheel. The size of the circle indicates the total level of grip at each wheel, the larger the circle the more grip is available. Green represents how much of the available grip is being used by cornering, orange by acceleration or braking. Diagram 4: Grip levels - cornering hard while accelerating gently The front wheels naturally tend to have more grip than the back due to the weight of the engine, however in the diagram above, much of this grip is currently being used to take the corner (but the driver still has a small reserve of grip which could be used if the corner tightened). If the level of lateral grip at the front wheels is exceeded, understeer would result. The rear wheels are accelerating gently, but require less grip to corner as this role is mostly performed by the front wheels. If the driver was to accelerate more aggressively the sum of the lateral and longitudinal tyre forces would exceed the level of grip available at the rear and oversteer would result. ====================================================================== # Donuts URL: https://www.drivingfast.net/donuts/ Category: Techniques What kind of car do you need? Rear wheel drive is essential to perform sustained doughnuts, and you'll need enough power to spin the rear wheels and keep them spinning. This is a technique you won't want to use too frequently unless you have a set of rear tyres which you don't mind wearing out! Make sure all stability control systems are turned off, and it you are in an auto, lock the gear in first if possible. Do not attempt this technique on the public roads! How to do a doughnut You can perform a doughnut in two slightly different ways and you don't need to be too hard on the clutch to pull one off. You can either have a rolling start, or spin the wheels from a standstill... 1. Spin the wheels. It's slightly kinder to your car to have a rolling start, this will allow you to fully release the clutch before inducing wheel spin. Approach the area where you want to perform the doughnut in first gear at low speed, ensure you're completely off the clutch then turn in hard and apply full throttle rapidly. 2. If you have enough power you'll find the rear wheels start to spin. Keep the revs up high in the power band and apply a certain amount of steering lock . Alternatively you can spin the wheels from a standstill while applying some steering angle to have the same effect. 3. You should find that the rear wheels lose traction and begin to cause the car to rotate, keep the revs high (you can even remain on the limiter if fitted) and you should complete a doughnut. You can modify the direction by steering at different angles and altering the throttle. 4. If you want to drive away from a doughnut ensure you make the necessary counter-steering adjustments early as the car will have a tendency to oversteer. In summary a doughnut is a relatively simple and dramatic technique to perform with the right car. ====================================================================== # Drifting URL: https://www.drivingfast.net/drifting/ Category: Techniques There are many different methods of inducing oversteer, your choice depends on the properties of your vehicle. Once oversteer has been invoked, you'll need to control the drift using the throttle and counter steering. To maintain an accurate line while going sideways is tricky, and will take lots of practice. Many different drifting track days are emerging such as the annual Autocar 'Sideways Challenge' (in the UK) where you can learn this art. What kind of car do I need to drift? Rear or four wheel drive with a rear bias Lots of power is useful A limited slip differential to keep both rear wheels spinning, rather than just one The ability to turn off any electronic stability control systems Cheap rear tyres! You can't drift properly in a front wheel drive car - you can oversteer temporarily, but it's impossible to sustain a drift correctly without rear or four wheel drive. Stages of the drift We've split the drifting process into four main stages shown in Diagram 1 below. A. Turning in B. Inducing oversteer C. Controlling and sustaining the drift D. Exiting the drift Diagram 1: The four stages of drifting A. Turning in When learning to drift, our advice is to approach a tight 30mph turn in second gear at about 3000rpm - this will give you a decent amount of torque to keep the rear wheels spinning once you've induced oversteer. Remember drifting is not the fastest way round a corner so you're not trying to set speed records here. Turn in and aim to apex about half way round at the geometric apex (the green line in Diagram 1 above). If apex too soon you can find that the car will run wide and you'll have to compensate by ending the drift early, too late and you'll be on the straight early and won't have any time to sustain the drift. With practice you'll be able to drift round the corner in a smooth arc which follows the racing line. Once you have mastered drifting along the racing line, you'll then be able to start the drift earlier and sustain it for the entire corner, and even adjust the angle or steering simply by adjusting the throttle. B. Inducing oversteer At the apex of the corner you need to initiate oversteer, which sometimes is more difficult than it sounds. Drifting has developed its own unique terminology for techniques to 'get the back out' which are explained below. Remember that if you have a modern car with clever electronic stability control systems you'll need to turn these off first.? Power / Power over / Power slide If you have a powerful car it should be possible to break traction simply by accelerating sharply mid bend - this is the preferred method of inducing oversteer as it is easy to control and repeat. If you increase the throttle too slowly it's unlikely anything other than understeer will occur, too hard and the car may spin. You're aiming for a sharp, sustained hit of power in the right gear - practice will help you get the balance right. You might be surprised about how much power is required on a road with a good surface, so it might be helpful to chose a road which is either damp or has lower traction tarmac. Clutch Kick Clutch kick is a useful technique to use if you do not have a particularly powerful rear wheel drive car. The trick here is to enter the corner and dip the clutch. Raise the engine revs to near the red line, and then release the clutch at the apex. The resulting shock load of torque sent through the driveline should break traction at the rear wheels, thus invoking oversteer. Changing down / Shift lock "Shift lock" describes the action of locking the rear wheels momentarily by changing down a gear (or two) rapidly without rev matching. Once you're back on the gas this will give you the benefits of more torque at the wheels due to the lower gear, with high revs helping sustain the drift. Lift off / braking Entering a corner fast, then lifting off the accelerator at the apex can cause oversteer due to the resulting forward weight transfer which reduces grip at the rear tyres. If you drive a particularly stubborn car, a quick dab on the brakes may help. Article on lift-off oversteer Handbrake / E-brake If your car refuses to get tail happy, there is always the option of the handbrake / emergency brake. A sudden sharp application and release mid corner will break traction at the rear wheels, but remember to keep your thumb on the release button! Get on the throttle as soon as the back steps out. Scandinavian flick / feint Flicking the car the opposite direction to the corner, just before turn in will generate a rapid lateral weight transfer which can unsettle the car enough to flick the back out. As soon as you turn in, get on the gas and prepare for the resulting oversteer. Article on Scandinavian flicks Jump drift This is probably one of the more risky methods - the trick here is to put two wheels onto the inside edge of the track while cornering, with the resulting bump unsettling car enough to break traction at the rear. Use with caution! Suggested methods of inducing oversteer Inducing a drift Most of the above methods can be used in combination (for example a 'Scandinavian flick' combined with 'lift off'), but you'll need to experiment with your own car to see which work best. C. Controlling and sustaining the drift Once the back starts to come round (1 in Diagram 2) you need to act quickly. Keep the power on (you might be surprised how much power is required to sustain the drift) and quickly counter-steer in the desired direction of travel (2), and balance the throttle to alter the attitude of the car. Diagram 2: Catching the drift To sustain the drift you need to keep the power on to keep the rear wheels spinning - about 80% throttle is the rule of thumb (although you'll need less in slippery or low traction conditions). If the back comes round too far, gently ease off the throttle and apply additional steering lock to correct the slide. If you're finding it hard to keep the slide going, you may need to use more power or take the corner slightly faster. Diagram 3: Sustaining and ending the drift D. Ending the drift Finishing the drift and getting the car straight again can be tricky - if you end the drift too quickly you might find the car starts to oversteer in the opposite direction, leading to 'fishtailing' and a pendulum effect which can be hard to control. The trick is to ease off the power smoothly and turn the steering rapidly and decisively back to the straight ahead position. Don't let the steering run through your hands as this won't give you the control you need. Preparing a drift car If you decide to get serious and have a car specially for drifting, you should consider a series of relatively simple modifications. Suspension It's a good idea to try and reduce body roll and thus increase control due to a more consistent tyre contact patch by fitting stiffer springs and dampers. Adjustable ride height and damping will allow you to tune the suspension to your personal tastes. Fit stiffer anti-roll (sway) bars particularly at the back, which should be stiffer than the front to provide a good turn-in and reduce understeer. And if you're feeling really keen, a few degrees of negative camber on the front wheels will further reduce understeer and give you a nice sharp steering response. Engine, drive-train and electronic aids As drift cars tend to put the engine under high load and the angles they are driven at prevent an efficient flow of air through the radiators it's sensible to fit cooling upgrades for radiator and oil. A limited slip differential with a decent amount of lock up torque is preferred, but budget racers may opt for a welded diff, which shouldn't be used on the road. Clutch upgrades are also a good idea, especially if you're using the 'clutch kick' approach to inducing oversteer. Electronic traction aids should be completely disabled, which may involve the removal of a fuse in cars with over protective systems. Tyres Slick rear tyres or tyres with low tread are ideal for drifting. Rear pressures can be increased if you're finding it difficult to get the back out. The best drift tyres have a stiff sidewall which reduces deformation under heavy load and gives a more predictable drift. ====================================================================== # Driving corners fast URL: https://www.drivingfast.net/tackling-corners/ Category: Techniques Once the optimum route through the corner has been determined, it's time to negotiate the turn in the quickest way possible. To do this will, you need a decent knowledge of your car's limits, some time to learn the track, and a combination of car-control techniques. It might be worth reading our introduction to the racing line before reading this article. The corner (including the sections of track immediately before and after) can be divided into distinct zones which are shown in Diagram 1 below. Acceleration zone (prior to cornering) Pedal transition Braking zone Gear change Turn-in point Neutral throttle (or trail braking for experienced drivers) Apex point Acceleration (after hitting the apex) Full power Diagram 1: Driving the racing line Acceleration zone To get the best times on the track you need to be either accelerating or braking at all times while on the straights - any coasting means you're losing precious seconds! Try to accelerate all the way up to the braking zone and use maximum throttle up to the last point. Pedal transition Before you can begin braking, there is a short break as you release the throttle and apply the brake with your right foot. Left foot braking is an advanced technique which can reduce this time to the bare minimum. Braking zone Apply the brakes hard at your predetermined braking point using the threshold braking technique. Due to the forward weight transfers, there is a possibility that you may lock up one or more wheels (or activate ABS), but as you're travelling in a straight line this will not necessarily cause any detrimental effects. Ensure that you have come off the brakes, or reduced braking to a minimum before you turn in. As you learn the track and your tyres warm up you will be able to leave the braking point later. Trail braking Once you have mastered the racing line and the various stages of driving through a corner shown in Diagram 1, you might consider taking things one step further with trail braking. This involves braking later and continuing to brake into the early phase of the corner before the apex. This can help improve your lap times, but also pushes your car closer to the limits of grip. Trail braking should be considered in the following situations: If you have a car which is prone to understeer when turning into a corner If you have accidentally left your braking too late and need to further reduce speed to be able to take a corner If you have perfected the racing line and the phases of cornering and are looking to further improve lap times 1. If you have a car which naturally has a tendency to understeer, feathering the brake into a corner will maintain a forwards weight transfer and can provide additional grip at the front wheels. This can sometimes allow a faster cornering entry, but the success rate depends on the setup of your car. 2. If you find you have ploughed into a corner too fast and feel that there is a risk you might not be able to remain on the track , trail braking can help. Remember though that the less braking you can get away with mid-corner the better. So only use as much braking as you absolutely need to - this will leave you with greater reserves of grip which can be used to keep you on the track while cornering. This technique should be treated as a method of recovery rather than a matter of habit. 3. Once you have cornering down to a fine art, trail braking is a method of further improving your lap times. When performing this technique at speed, it's important to remember that the majority of the braking should still be completed in a straight line. However to squeeze every last ounce of performance from your car, you can start to leave your braking point slightly later and continue to use the brakes in the corner prior to the apex. Before you turn in, progressively start to ease off the brakes until they are fully released at the apex ready for the acceleration phase. Some cars do not react well to trail braking, especially those prone to lift off oversteer - although there will be more grip available at the front wheels while trail braking, the rear will be more prone to break loose. Beware! Gear change Before you turn into the corner you'll usually need to change down. The golden rule here is to select a gear which will allow you to accelerate out of the bend efficiently. Heel and toe shifting can be a useful technique to master here as it allows you to brake and change down simultaneously while avoiding transmission shock loads which can unbalance the car and cause unwanted weight transfers. Article on heel and toe shifting Turn in point The turn in point When turning in, ensure your steering motion is smooth and progressive. The perfect corner involves tightening the steering until the apex (see diagram above) and then gradually unwinding the steering lock. If you find yourself increasing or correcting the steering lock as your travelling through the corner after the initial turn-in you've probably taken the wrong line. Balanced / neutral throttle The largest demand on the grip reserves of your tyres occurs between the turn in point and the apex. It is vitally important not to place additional demands on the tyres by accelerating or braking. This isn't to say you can't retain a constant speed, but the important factor is that the car is in a neutral state until after the apex. Understeer or oversteer are most likely to occur at this point. Clipping the apex When hitting the apex don't be worried about cutting the corner slightly. During a corner, the weight is transferred to the outside wheels, and thus these are doing most of the gripping. Putting the inside wheels onto the rumble strip or slightly into the gravel shouldn't be too much of an issue. Post apex acceleration Once you've hit the apex, you should be able to start reducing the amount of steering lock. As you are doing this progressively increase the throttle up to the point of full power. The point at which you can apply full power depends on your car. Some cars will be able to apply full power straight after the apex, depending on the severity of the corner and the conditions. The next corner By now you should already be thinking about the next corner and position your car appropriately to allow you to use the racing line, this may affect your route and the first corner may require a compromised line. Factors which affect cornering speed The overall speed at which you can take a corner depends on a vast number of factors including your experience, the handling of your car, and the conditions of the track. For example, a turn with a beneficial camber can dramatically increase the speed that can be sustained. It's really important not to second guess cornering speeds but build up the pace gradually lap by lap until you feel the limits of grip approaching. General note All of the above guidance depends on your driving style and the car you're using. You will not be able to use all the power of a Bugatti Veyron or McLaren F1 until you're completely in a straight line, however if you're in a lighter less powerful car you can apply the gas much closer to the apex point. It's very rare to achieve the perfect corner, it takes knowledge of the track and the car and a great deal of practice! Article on overtaking on track corners ====================================================================== # Getting a good start URL: https://www.drivingfast.net/off-the-line/ Category: Techniques Get off the line before anyone else and you'll have an immediate advantage by being able to defend your position with the added bonus of having the ability to chose the ideal racing line. The technique is outlined below. Consider the road / track surface If you are able to choose the position of the car, consideration should be made to the traction of the tarmac. If you're on the race track on a starting line, chances are there will be rubber on the track from previous cars spinning their wheels. In the dry, positioning your driven wheels over this rubber this provide more grip, however in the wet the reverse is true. Once you have set your start position, ensure your wheels are straight and this will help transfer as much power to the ground as possible. Wheel position Position the driven wheels on tyre marks in the dry On tyre marks ... but straddle tyre marks in the wet Straddle tyre marks In a manual transmission car: 1. Set the engine speed Set and hold the revs in your engine's power band. If you're familiar with the car you'll know instinctively where this is, but when starting with a new car consider having a look at the power and torque curves. A Honda Civic Type-R has a very different power delivery to a Porsche 911 Turbo. Note: Don't 'blip' the throttle, as you won't be able to accurately set the revs. 2. Release the clutch progressively Never dump or 'sidestep' the clutch. This will result in a massive shock to the transmission, and almost certainly produce uncontrolled wheel-spin (less likely in a four wheel drive car). Instead, release the clutch progressively, and counter the drop in revs with a slight increase on the throttle. Limit the wheel-spin using a combination of clutch slip and throttle control, and try to fully release the clutch earlier rather than later. In the wet, it can be a good strategy to pull off the line gently then gradually squeezing on the power, thus keeping wheel-spin to a minimum. 3. Squeeze on the power When you're off the line it's still critical to keep throttle application progressive, especially in a powerful car or in the wet. Accelerating too hard can lead to 'fish-tailing' and prevents power from transferring to the track. In a car with automatic transmission: 1. Left foot brake Use your left foot to keep the car stationary. 2. Increase the engine speed Use your right foot to push the throttle slightly, this will take up the slack in the gearbox and allow the revs to increase closer to he power band. Don't do this for prolonged periods as it can lead to gearbox overheat. 3. Release the brake and increase the throttle Come off the brake and increase the throttle quickly, but progressively. If you've left two black marks in the road you're being to aggressive! ====================================================================== # Handbrake turn URL: https://www.drivingfast.net/handbrake-turn/ Category: Techniques Handbrake turns are frequently used in rally driving to negotiate tight, lower speed corners and can be useful in a variety of low speed maneuvers and stunts. This method of turning tight corners relies on the fact that handbrake usually operate on the rear wheels, which lock when it's pulled on hard. This allows a slide to be induced and a tighter radius or corner will be completed. Note that this method of taking a bend will only be quicker than the conventional racing line if the corner is very tight. Handbrake turns are also a method of inducing oversteer for drifting, and can be used in conjunction with the Scandinavian flick. How to do a perfect handbrake turn When practising handbrake turns, it's best to use a low friction surface to make it easier for the back end to slide and to prolong the life of your tyres. Here's an overview of the maneuver, which we've split into six stages (explained below). Overview of a successful handbrake turn Stage 1: Approach the corner at a reasonably low speed (no more than 30mph is a good rule of thumb, when learning). Use first gear when you're starting to learn, then try higher gears for complete mastery. Before you turn into the corner, swiftly come off the gas to create a forwards weight transfer and provide maximum grip at the front end - you'll need this to allow a swift turn in. Stage 1 Position your hands in a way which allows you to take big bite of the steering wheel and turn in a single fluid motion. A suggested initial hand position to take a left hander and the direction of turn is shown below. If you're in a left hand drive car, the right hand is optional and vice versa - you'll need the other hand to operate the hand brake half way through the maneuvers. You'll find it easier if the hand doing the steering is pulling the wheel rather than pushing it - but it is possible to do the turn in both directions with practice. Steering position Stage 2: Turn in hard in one fluid motion and aim to apex half way round the corner Stage 2 Stage 3: Simultaneously press the clutch and slam on the handbrake in a rapid and positive motion, ensuring you are holding down the release button to prevent the ratchet engaging - you'll need to release it just a quickly.This will lock up the rear wheels and induce a slide and start to tighten up the radius of the corner. Stage 3 Stage 4: As the back of the car comes round, start to take off the steering lock you initially applied. You may need to let the wheel slip through your hand in a controlled way. You need to end up with the wheels pointing in the direction you want to go. Stage 4 Stage 5: This is the tricky bit - when the car has rotated to the desired amount, release the handbrake, knock into first gear if necessary, and bring out the clutch with enough revs to spin the wheels slightly. This will give you the best possible start in the new direction. Counter steer if necessary if you've overcooked the angle. Stage 5 Stage 6: Pull away using the same throttle technique as the perfect start. Stage 6 When done correctly, stages 2 to 5 should only take between only two to three seconds - this is a rapid series of fluid motions. When learning this technique, it's best to practice in a smooth wet grassy field with plenty of room. Common mistakes: Approaching the corner too slow - this will prevent you from getting the required amount of rotation Approaching the corner too fast - this can result in an uncontrolled spin, or understeer preventing you from keeping the required line as you turn in Holding the handbrake on for too long - this will make the car rotate further than you wanted ====================================================================== # J-turn URL: https://www.drivingfast.net/j-turn/ Category: Techniques This is predominantly an evasive driving manoeuvre or stunt, but is also a lot of fun. When trying to learn this technique, it's worth using low grip surfaces such as a grassy field or a wet area of tarmac. Once you're confident, you can work up to dry tarmac, but you will need more speed which means things could go wrong faster. The beautiful thing about J-turns is that you don't need a performance car to pull one off. Overview For the purposes of this article, we will demonstrate an anti-clockwise j-turn and split the technique into four stages, which combine to form the complete manoeuvre (shown below). Overview of the J-turn Stage 1: Start off in reverse gear, make sure the coast is clear behind you and turn your head so you're looking out of the rear window. When learning to pull off the perfect j-turn, you'll find that your finishing position may not be exactly in line with where you started off, so make sure you have lots of room to the either side or the car as well as behind. Now accelerate to between 15 and 25 mph (depending on how slippery the ground is) and keep the power on. You can steer with one or two hands, our suggested steering position shown in Figure 1 below. Step 1 Figure 1: Steering position Stage 2: Come off the power rapidly (transferring the weight to the back of the car) and fractionally later quickly apply half to three quarters of a turn of steering lock rapidly. Watch out as the front of the car swings round to the left, so ensure there are no obstacles there. Step 2 Stage 3: The next step depends on the type of car you're driving. There are two basic methods one of which uses the brakes (easiest) and one doesn't (more difficult). If you have ABS fitted, you will not be able to use the brake method as it will be impossible to lock the wheels, so read the paragraph that applies to your car below: A. Front wheel drive, manual transmission, no ABS: Mid way through the turn, when the front wheels are parallel with the track, stab the brakes* and clutch. This will lock up the front wheels due to the fact most of the braking bias is towards the front. The momentum of the turn combined with the rear weight transfer will allow the front for the car to rotate round until you're facing in the opposite direction. When the front wheels are locked, select first gear. Now move onto Stage 4. If you would prefer not to lock up the front wheels, use option B. B. Front wheel drive, manual transmission, ABS: As you have ABS fitted you won't be able to lock up the front wheels as used in option A. This means it will be more difficult to select first gear when the wheels are rotating backwards so you need to use double declutching. To do this, press the clutch in and pop it into neutral, then clutch out briefly. Clutch in yet again and select first. This can be done as a rapid series of movements with practice, but adds complexity to this manoeuvre. C. Rear or four wheel drive, manual transmission, with or without ABS: It is very difficult to lock up the rear wheels when pulling off a J-turn, so the easiest method is to avoid the use of the brakes and double declutch to select first gear. To do this, press the clutch in and pop it into neutral, then clutch out briefly. Clutch in yet again and select first. This can be done as a rapid series of movements with practice. D. Automatic transmission, front, rear of four wheel drive, with or without ABS: If you have an automatic, this technique can be much easier to pull off - mid way through the turn, simply flick into neutral, then drive when you're pointing in the right direction. Some autos are more sympathetic, and in this case you'll be able to move straight into drive. Step 3 Stage 4: While the front of the car is rotating, start to reduce the amount of steering lock and prepare to pull away in the opposite direction to the starting point. When you're pointing in the right direction, ensure first gear or 'D' is selected, and release the clutch with enough revs to spin the wheels slightly, pull away using the same techniques as used in a perfect start. Step 4 Advanced tip: If you're finding it hard to get the front round, try increasing speed or use a quick flick of opposite lock before hand to unsettle the car (a reverse Scandinavian flick). See our article describing how to do a Scandinavian flick ====================================================================== # Racecraft - overtaking on a corner URL: https://www.drivingfast.net/racecraft-overtaking-on-a-corner/ Category: Techniques A crucial part of racing is overtaking and defending your position - this is where things get seriously fun. This article builds on the fundamentals of the racing line, which are worth reading before you move onto this topic. Now we know you're a sensible human, but please note that this is a track only technique and is inherently risky. You would be nuts to do this on the public roads, and on the track Racing line basics Driving corners like a pro Once you're familiar with the articles above it's time to apply these principles techniques to racing. A common overtaking strategy is to dominate the inside line of the corner in an attempt to make your opponent run wide on an non-optimal line - this advantage can help you gain a position, but it can also be defended against. We're going to learn about the offensive and defensive techniques. Let's quickly recap on the ideal racing line (shown below). If the track is clear you should be able to stick to this line and continue to put distance between yourself and competitors stuck in traffic behind, however a clear track doesn't usually last for long and you'll need to learn to continue to be fast with the distraction of other drivers. The racing line with late apex First, let's tackle this scenario - you've been gaining ground the car ahead of you and you're ready to try to overtake. He's been rudely blocking you on the straights so you're going to try and grab the inside line on a right hander to force your competitor to run wide on a slower line and claim your rightful place on the podium. Now, the default behaviour of everyone on the track will be to drive the optimal racing line and by now you'll understand how much slower it is when you don't follow this path. You want to use this to your advantage - we'll show you how in the steps below. Step 1: Get in the slipstream As you're chasing the car in front, it's worth exploiting the slipstream to use the bonus momentum just before the corner. Unless you're in a more powerful car, this might be essential to aid the overtaking manoeuvre. Article about the slipstream Step 2: Get a boost of acceleration Pull out of the slip stream before your competitor brakes for the corner. Use the burst of acceleration to pull ahead and to the side of your competitor to the inside of the corner. This is the riskiest part of the exercise - you need to rely on the driver noticing you in the mirrors and not turning into the side of you resulting in crashing, flames etc. They will probably be annoyed so might do this anyway. If they do, you need to be on the ball and may need to abort the move by applying the brakes and moving back to your original position. Step 3: Force them wide Now it's a battle of inner strength - if you do manage to hold the inside line you will have naturally forced the guy in front to follow a wider (and slower arc) through the corner. You'll be on a more natural racing line and should be able to continue passing and accelerate away. Remember to wave or use an obscene gesture, depending on your personality type. If they are really good, they can defend against this (discussed below). Step 4: Prepare for the next corner As we know, the ideal racing line depends on a number of factors, not least the position and proximity of the next corner. If we were writing this for a TV show, we would call it the two Ps of the racing line, then trademark it, then become millionaires, then elected president. But we're not. We're broke. Anyway, if there is a long straight immediately after the corner, there's a relatively strong change you can hold this position if you block your opponent. However, if you're holding the inside line and the next corner is another right hander and it's pretty close, you may well have screwed up. Probably should have mentioned this at the start. And this brings us onto the topic of defending against overtaking on a corner. Defending your position in corners Remember, to gain position you have hogged the inside line, and you've probably taken an early apex to force your competitor wide. In other words you compromised your line for position, and if your opponent is wise they may be able to use this to their advantage and get you back. An early apex means you'll now need to run wide to maintain speed, sometimes very wide. And if you're running very wide you may need to ease off the gas to not leave the track entirely. And if you're easing of the gas early there is every chance you'll lose position on the next corner. This is why racing is such a great sport - you have to make lots of rapid decisions some of which can be relatively catastrophic - sometimes you need to be brave, sometimes you need to be calm. So let's switch roles now. You are in the lead (naturally) and some pesky newcomer thinks they're going to muscle through on a turn. But you are wise - you have read all of our articles on the racing line and probably donated large sums of cash to us as a thank you. You're fundamentally a great person. This guy has been on your tail for a while, his parents probably gave him his racing car for Christmas and it's been to that tuning house you can't afford. But you're a champion. He attempts to push through on the inside but you don't make it easy for him, forcing a very early apex. He gains position and tries to pull away from you but has to run a very compromised line. You apex later and have a more optimal exit gathering momentum more quickly. If you're smart, this loss of position will only be temporary - by gaining an advantageous line you will have a great exit speed which can be used to re-establish your lead either on the straight or the next corner - the battle continues! The above scenario is outlined in the diagram below. Overtaking on a corner ====================================================================== # Racing line URL: https://www.drivingfast.net/racing-line/ Category: Techniques The racing line is the route a racing driver follows in order to take corners in the fastest possible way. By using all of the available space on the track, cars can travel in a straighter line and travel faster before reaching the limits of grip. Determining the best line is an essential skill to master for both track days and racing events. The best line depends on the following factors: Braking point Turn in point Apex The position and direction of the next corner It is important to remember that there is rarely a perfect line through any corner for all circumstances. It depends on the characteristics of your car, your cornering strategy and the conditions. If you may also have to react to the position of other cars on the track. You should experiment with different lines and learn from instructors and people who know the course well. Braking point How good are your brakes? How quickly can you reduce your speed from 100mph to 40? How does your car behave when the front wheels are locked? How brave are you feeling? All these factors determine your braking point. It's a sensible strategy to brake earlier when you're learning the track and your car, and progressively shorten the braking area as your experience grows. The rule of thumb is to get most of the braking out of the way before turning into a corner, although a slight brake pressure on entry can help to reduce understeer and can give a better turn in (this is known as trail braking). Threshold braking is the technique you should aim for, but if the wheels do lock, quickly ease off and reapply the brakes with slightly less pressure until you get it right. Try not to turn in if any of the wheels have lost traction. Turn-in point To get the line right, it is vital to turn in at the correct point. Leave it too late and you'll miss the apex, too soon and you'll have to tighten your line mid corner. Get this right and you'll have set yourself up for a good line. Remember that the apex may be further round the turn than you can see, so make sure you learn the track and the apex points before driving in anger. On track days, there are often cones on the track to help new drivers learn the track - but even when the cones are gone there are often visual clues which you can use, a good instructor will be able to help you find them. Apex The apex is the point at which you are closest to the inside of the corner, also referred to as the clipping point. Once you have hit the apex you will be able to reduce the steering lock and increase the throttle. Determining the apex can be tricky but the guidelines below explain how to do it. The geometric apex of a corner There are two different types of apex, the geometrical apex and the racing apex. The geometric apex of a constant radius corner is the central point on the inside and this may also be the racing apex, which depends on the context. Confusing! This is where your strategy comes into it, especially when you're racing. There are two main strategies for cornering: Minimising the severity of the turn and carrying speed through the corner (great for less powerful cars or when driving in the rain) Getting the power on early for a faster exit speed (great for powerful cars and when racing) The geometric apex - carrying speed and minimising the turn severity To carry maximum speed through a corner, you need to take the route that minimises the tightness of the corner arc. This minimises cornering force and frees up precious grip for maintaining speed. This route tends to use the geometric apex of the corner and is usually known as the classic racing line. In Diagram 1, the turn illustrated is a constant radius 90 degree right hander and the geometric apex is exactly halfway around the corner. Diagram 1: The traditional racing line Advantages of the classic / traditional line: Smooths out corners in the most efficient way Maintains momentum (can be useful for low powered cars) Reduces the chances of understeer or oversteer (especially helpful in the rain) Preserves the life of tyres Disadvantages: Not necessarily going to yield the fastest possible lap times Late apex - getting the power on early Oddly enough, carrying the highest average speed round corners may not actually be the quickest way around a track. If the corner leads onto a straight it can be better to take a late apex, straighten out the car and get the power on earlier for a high speed exit (Diagram 2). This is generally regarded as the best strategy for racing, with a slightly lower entry speed but a faster exit speed. The amount of grip available is the factor which determines how late you can brake and apex. Diagram 2: The racing line with late apex Advantages of the modern racing line: Increases the chances of a fast lap in a powerful car Allows the power to be applied earlier Maximises the use of any straights following the corner Allows late braking Disadvantages: May not be the fastest route in a low powered car Places greater demand on the tyres Common mistake: It's very common for drivers to apex too early due to nerves about the approaching corner and eagerness to take the turn. The racing line apex which is often out of view at the point of turn in, or further round the corner than you expect (see Diagram 3 below). This is where experience and track knowledge come in. Diagram 3: Comparing the geometric and racing apex Hairpins A hairpin is a corner which turns about 180 degrees. In this case, the apex for the racing line is about three quarters of the way around the bend (see Diagram 4). A useful guide is that halfway through the turn you should be roughly in the middle of the track. Diagram 4: The racing line for a hairpin The position of the next corner The position and direction of the next corner also affects the choice of line. For example, if the next bend is a left hander you'll need to move over to the right hand side of the track, and thus will need to apex later and take a tighter, slower line. However, if the next corner is another right hander a wider, faster arc can be used (see Diagram 5). Diagram 5: The racing line depends on the position of the next corner to illustrate the points covered in this article, take a look at this short clip from the MotoGP, where you can clearly see the racing line the bikers are taking on the wet track. Now that you know the fastest line through a corner, it's time to learn how to drive corners competitively. Next read the article on driving corners at speed ====================================================================== # Scandinavian flick URL: https://www.drivingfast.net/scandinavian-flick/ Category: Techniques The tightest corners and hairpins usually require the use of a handbrake turn, but the flick can be used in conjunction with, or without the handbrake. The name arose from the Finnish and Swedish rally racers of the 1960s who widely used it with great success. To perform the Scandinavian flick, you need to have an understanding of grip and weight transfers, and have a low friction surface to practice on - wet grass and gravel are ideal. It can be performed in both front, rear and four wheel drive cars but it's important that the car doesn't suffer from serious understeer - if it does you'll find it difficult to turn in on slippery surfaces at speed. Performing the technique The stages of the flick are outlined below. Figure 1: Stages of a Scandinavian flick 1. Set yourself up for the corner slightly to the outside of center. You don't want to take the racing line here as you need to have room on the outside of the corner. Get all of your braking out of the way in a straight line and ease off the brakes when your cornering speed is reached. 2. Turn briefly towards the outside of the corner, using trail braking if necessary (feathering the brake into the corner) to reduce any understeer you might experiecne. You don't want to take a lot of time over this motion, just enough to create a weight transfer to the inside wheels. 3. Almost immediately turn in sharply in the correct direction of the corner. When done properly, the reverse in weight transfer to the outside wheels should unsettle the rear of the car enough to break traction. 4. The back of the car will start to come round - this tightens the radius of the turn and thus allows quite tight corners to be taken at speed. Counter steer if necessary to keep the car heading in the desired direction. Once you're past the apex of the corner, gradually reduce the amount of steering lock. Once you have completed the corner, apply progressive throttle to accelerate out of the corner. Figure 2: Counter steering Note that experienced rally driver may do may of these stages simultaneously while using techniques such as left foot braking. A video from the incredible Colin McRae which demonstrates the Scandinavian flick: --> ====================================================================== # Threshold braking URL: https://www.drivingfast.net/threshold-braking/ Category: Techniques Threshold braking is the art of slowing down in the quickest possible way by maintaining brake force at the optimum level. It's tricky and requires a lot of practise in a familiar car before you'll be able to do it reliably, but braking late before a corner is one of the easiest methods of getting decent track times. But first, two quick facts: Locked wheels are not the most efficient method of slowing down (lots of tyre screech is bad) Tyres exert maximum braking force when slight wheel slip is occurring (some tyre screech is ok) Is threshold braking still relevant in a world with ABS? In a word, yes. ABS is a reactive system - is detects the onset of a locking wheel and reduces the brake pressure automatically until the wheel has regained grip. When threshold braking, the driver attempts to maintain maximum deceleration without locking wheels, so if ABS has kicked in, then something has gone wrong. However, many modern ABS systems are react so quickly to changing conditions that it is becoming more difficult to improve on them, but the best drivers still can - and many track cars do not have ABS. So, how does one learn this strange and wonderful technique? Stage 1 First you need to become familiar with the point of wheel lock in your car First you need to become familiar with the point of wheel lock in your car, which means finding suitably safe area of privately owned tarmac to practice on. Brake hard in a straight line at different speeds (30mph is a good starting point) and get a feel for how the car reacts under rapid braking to the point of wheel lock. Don't stamp on the pedal, but rather apply push it firmly and progressively. Get the answers to the following questions clear in your own mind: How hard do you need to push the pedal for wheels to lock (or ABS to kick in)? What is the sensation just before the point of wheel lock? When wheels do start to lock up, what are the warning factors? Which wheels lock up first? How does the car behave when a wheel has locked? Is there any feedback from the brake pedal? Once you have the answers to these questions, it's time for… Stage 2 Now you're familiar with the sensation of braking hard enough to lock wheels in your car or activate the ABS. Remember, as soon as wheels lose traction with the tarmac you're no longer braking efficiently - but even the best drivers lock wheels from time to time. So, it's important to learn how to regain maximum friction as quickly as possible when this situation arises. Accelerate to a slightly higher speed (say 50mph) and repeat the process of inducing wheel lock. Try to get to the point of lock as quickly as you can without upsetting the balance of the car. But rather than simply screeching to a halt, release the brake slightly to free up the locked wheel(s), then reapply at a slightly reduced pressure to try and maintain decent braking performance. Get to the point when you can reliably reduce the brake pressure and reapply the brakes in as little time as possible. Some ABS systems may make this process difficult due to built in delays in the electronics, and it might be at this point when you decide threshold braking isn't for you after all! Stage 3 Now you will have a good feel for the car, appreciate the sensation of heavy braking and understand the point of wheel lock, so it's time to do the perfect run. Accelerate back up to around 50mph and repeat the process of braking heavily, but this time try to come to a halt as quickly as you can without locking any wheels. Remember, a little bit of tyre screech is ok, as long as the wheels haven't locked. If a wheel does stop rotating, use the 'release and reapply' technique to maintain control of the car. Repeat as many times as you need to until you can brake reliably without locking wheels - give yourself a pat on the back and check your tyres for wear and tear before going back on the public roads. Now all you need to know is how to do it in different track conditions! ====================================================================== # Slipstream overtaking URL: https://www.drivingfast.net/slipstream-overtaking/ Category: Racecraft Picture this scenario - you're competing in a race series with identically powered cars and you'd like to pass someone on the straights - how do you do it? There are several techniques which could be used, and ideally combined. One of which is driving a better line to exit the corners faster, or braking later, but here we're going to take a look at 'drafting' or using the 'slipstream'. Behind a moving car, there is an area of turbulent air which is at lower pressure than the surrounding atmosphere. This low pressure zone can be exploited to maintain the same speed of the car in front while using less energy. Exploiting low pressure zones can be highly effective, it's how aircraft wings and sails work and why geese migrate in a v-shape. Using less energy to maintain the same speed means you'll have some spare performance on tap, which can be used to overtake your rival. We would never lie to you, but just to prove it exists let's take a look at the slipstream in action with this cycling speed record attempt - skip to the middle bit. https://youtu.be/wT0eJXtrwHg The size and usefulness of the slipstream depends on how fast you're travelling, and the shape of the car in front. In general, the more aerodynamic, the less effective drafting will be - but you can use this technique with any car. To exploit the low pressure area you will need to be quite close, which is obviously a risky place to be as you approach a corner - at some point they will hit the brakes hard and for this reason the technique is used the most on long straights. Watch this incredible overtaking manoeuvre as Lewis Hamilton exploits the slipstream to gain the dominant inside line on entry to the corner, brave but risky. https://www.youtube.com/watch?v=0T5-D-be8aA As you approach the slipstream of a car in front, you should be able to maintain the same speed with slightly less throttle than your opponent. To overtake, you'll need to use full throttle at the opportune moment, and then use this burst of acceleration to gain momentum then pull out and around the car ahead. Just like Hamilton you can use this advantage to grab the dominant line and nudge ahead one position. A word of caution - if you in a car equipped with downforce, while you're in the slipstream the low pressure will temporarily reduce the amount of grip available which can lead to understeer, crashing and crying. ====================================================================== # Driving position URL: https://www.drivingfast.net/driving-position/ Category: Track It's vitally important to get your driving position right before driving on the track. Your seat and steering wheel position should be adjusted carefully to... Allow grip of steering wheel even in extremes of motion (e.g. when being thrown about it corners) Ensure mechanical efficiency of your body (you'll be tired after 20 laps) Maintain maximum visibility Prevent any obstructions (e.g. knees on the steering wheel) Give you maximum control of the car Tips for correct seat positioning on the track If you have harnesses, your back will be pushed firmly into the backrest- so when adjusting your seat, make sure you use this position as reference. Arms: Let's start with the arms - you should be able to comfortably rest your wrists on the top of the steering wheel without leaning forward (Diagram 1). Diagram 1: Your hands should have freedom of movement around the entire wheel (not just the top half) and if your hands touch your knees at any point (Diagram 2) or if your elbow hits the door, consider investing in a smaller wheel. Diagram 2: Your default steering position should be at the 'quarter to three' position so ensure the steering wheel is adjusted to allow maximum comfort (Diagram 3). Diagram 3: If you have an adjustable steering wheel, you might consider bringing the wheel slightly closer than you would have it when driving on the road to provide maximum control. Getting the driving position right means you'll be able to tackle tight corners easily, and even if you're fighting to remain in control you'll be able to keep your hands on the wheel. When you feel like the position is right, try testing it using a serious of movements in the 'worst case scenario' position (Diagram 4) Diagram 4: Note: If you're using harnesses, once you're bolted into your seat it's unlikely you'll be able to reach as far as usual so make sure you adjust your mirrors and any other gadgets before-hand. Leg position Legs are easier to get right than the arms. The rule of thumb is to sit in a position which allows you to fully press the clutch and accelerator to the floor while maintaining a slight bend in your knee. The brake usually moves less then the other pedals so is less important in this respect. Make sure that your knees aren't making contact with the steering wheel, and mimic a complete revolution of the steering to ensure freedom of movement. Back position When driving on the track, most drivers adopt a more upright seat position than when on the road. This ensures proximity to the wheel and good visibility, which can lead to better control than a more relaxed position. Seat height If you're tall or usually have your seat set high, headroom can be an issue when wearing a helmet. An inch or two of clearance is a must - banging your helmet repeatedly on the roof or on roll bars can cause damage. Everything else is a matter of comfort - remember that the priority should be to create an environment where you have maximum control over the wheel and pedals, and good freedom of movement. ====================================================================== # Engine & driveline URL: https://www.drivingfast.net/developing-a-track-car/ Category: Track The following points are the most crucial factors to take into account when considering the engine and drive-line layouts of a car for the track. The moment of inertia (flywheel effect) The moment of inertia is a physics term which describes how difficult it is to turn an object. Think about a hammer with the head at one end versus the head in the middle. The one with the head in the middle will be much easier to rotate around the central point as most of the weight is concentrated there. Moment of inertia The moment of inertia in a car varies depending on whether the heavier components are located close to the centre or towards the extremities. The more spread out from the centre, the more difficult it is to rapidly change the direction the car is travelling. Mid engine cars thus have the greatest natural agility. Weight distribution Weight distribution Many sports car manufacturers strive for a 50:50 weight distribution, and this is another important factor which contributes to the natural handling ability of the car. The closer you get to a 50:50 weight distribution, the more balanced the car becomes due to more equal weight begin divided between each of the four wheels. The weight acting on any tyre affects the level of grip it can provide, and cars with one axle providing more grip than the other can lead to handling issues on the limit. The division of grip demands for drive and steering A tyre can only provide a finite amount of grip and if you're using it all up by accelerating hard, there will be none left for cornering. The front wheels exert most of the cornering effort and in a front wheel drive car they also have to accelerate and provide most of the braking. The ideal scenario is to provide the drive via the rear axle, and allow the front wheels to concentrate on steering. Click here for more information on tyres and grip Front engine cars Front engine Front engine, front wheel drive Most commonly available, easy to find and cheap May need some tweaks to handle well on the track Front engine, rear wheel drive Good weight distribution Can be prone to oversteer If you're buying a road car to convert to a racing machine, chances are you'll end up with the engine in the front. The majority of cars on the road are front wheel drive due to the convenient packaging which means they're generally cheaper than alternatives. The front engine, rear wheel drive combination provides good weight distribution, but has a higher moment of inertia than mid engine varieties. In general, this layout has most of the advantages of much more specialist cars with very few drawbacks so can be a very good choice for a track car. The disadvantage of the front engine, front wheel drive layout is that the driven wheels have the additional demands of steering. This means if you're accelerating hard, less grip is available for cornering and this can result in understeer. The lighter rear end can also have a tendency to 'come round' if you lift off the throttle mid-corner, as the forward weight transfer reduces the grip at the back to very low levels. Mid engine (rear of four wheel drive) Mid engine Low 'moment of inertia' Easy to achieve 50:50 weight distribution If the engine is mounted between the rear axle and the driver, you're in a mid engine car. The main advantage of mid engine cars is that they have a low 'moment of inertia'. This means when cornering it is easier to turn the car to a new direction, thus increasing the manoeuvrability and stability. In addition, less rotational momentum is generated, which can lead to oversteer. Most sports car manufacturers aim for a 50:50 weight distribution to provide neutral handling characteristics, and with mid engine cars it is much easier to achieve this. Even though some front engine rear wheel drive cars may have a 50:50 weight distribution, they will have a higher 'moment of inertia' due to the majority of the weight being at the extremities. Think of twisting a hammer with a head at one end versus a head in the middle. An additional benefit of the mid engine layout is that the mass of the engine is more equally split between all four wheels which leads to naturally neutral handling characteristics. Rear engine (rear or four wheel drive) Rear engine High moment of inertia - it wants to keep turning even when steering has stopped and resists changes to rotation High available grip off the line and under acceleration. On paper, a rear engine car is a potentially unstable design. The heavy end generates much more momentum than the light front end and is more difficult to slow down and change direction. Think of an arrow flying in reverse! Rear engine cars can be prone to oversteer when lifting off the throttle or braking during a corner. Even when braking with locked wheels in a straight line you can find the back of the vehicle has a tendency to come round. Rear engine cars must be treated with respect - when oversteer is invoked it can be very difficult to control. Having said that, some of the best track cars of all time have been produced by Porsche and clever car setup and tuning can allow rear wheel drive to produce astonishing results. The front wheels are free to use all available grip for steering, and the weight transfers under acceleration provide plenty of traction at the back. Comparison of the natural characteristics of various drive and engine layouts Key: FWD = Front wheel drive RWD = Rear wheel drive 4WD = Four wheel drive Note that although a car may have relatively poor natural attributes, these can usually be addressed through vehicle setup and tuning. For example, the rear wheel setup of a Porsche 911 is not a naturally stable design but years of clever tuning has created a superb overall car. There are many excellent front wheel drive cars! Comparing different driveline designs with natural ability as a track car Moment of inertia Weight distribution Division of steering & drive Off the line grip Overall traction Handling Total score Front engine FWD ● ● ● ●● ●●● ●● 9 Front engine RWD ●● ●●●● ●●● ●● ●●● ●●● 17 Front engine 4WD ●● ●●● ●● ●●●● ●●●● ●●● 18 Rear engine RWD ● ● ●●● ●●● ●●● ●● 12 Rear engine 4WD ● ●● ●● ●●●● ●●●● ●●● 16 Mid engine RWD ●●●● ●●●● ●●● ●●● ●●●● ●●●● 22 Mid engine 4WD ●●● ●●●● ●● ●●●● ●●●● ●●●● 21 ====================================================================== # Engine modifications URL: https://www.drivingfast.net/engine-modifications/ Category: Track It's worth noting at this point that it becomes exponentially more difficult and expensive to increase performance through engine mods, and although you might find it easy to add an extra five, ten maybe even fifteen percent, after that a huge amount of cash will only yield modest gains in power. Motorsport has always been a hobby for the privileged, so if you're competing against millionaires it might be better to get into karting if you want to keep your house! An engine is actually a pretty simple beast, and achieving more power is a matter of increasing the volume of the raw materials, ensuring the bang is as efficient as possible and delivered at the right time, and ensuring waste gas is removes a quickly and efficiently as possible. Air in (induction): Induction All cars are fundamentally compromised as they come out of the factory. Even performance car manufacturers are constrained by various emissions laws, cost saving measures, and warranty concerns which means engines almost never achieve their full potential at the dealership. Fitting a cheap air filter in the factory probably won't affect sales, but this could save a car manufacturer huge amounts. As a result, helping the engine breathe better is one of the easiest ways of increasing performance, it's cheap and you can do most things yourself with a bit of mechanical knowledge*. *Don't modify any engine if you want to keep your warranty! Air filter: Air filters come in all sorts of different shapes and sizes and are there to prevent potentially damaging particles entering the engine. Smaller holes in the filter protect the engine better, but also restrict air flow. Clever design can improve the passage of air without compromising the engine, so at the very least you should replace the standard air filter with a higher performance version. Many filter upgrades are disposable so you'll need to stock up on a few for when you next service your car, some are reusable but will need cleaning periodically - make sure you follow the instructions to get the most out of your purchase. Pipes: Fluid dynamics is an fascinating science, but also fairly inaccessible to most people. To sum up in a sentence, gas flows better in specially designed pipes. Think of the transition when pouring a bottle of water from the glug glug action to the nice fast flowing stream, this is what you need to achieve with the air going into the engine. Even with your nice new air filter fitted, you'll still be limited by the inlet pipe design. In a Porsche you can be certain they've fitted the best possible turbulence free solution, but in bargain racers you can probably improve on the stock pipes. The major air filter companies such as K&N and Pipercross do a variety of 'induction kits' and if you dig around you can probably find one which is suitable for your car. These will consist of an air filter, and all the necessary pipes and fittings to get the air into the engine as fast and smoothly as possible. Exhaust: Exhaust Now that the air is entering the engine in a nice smooth stream you'll need to make sure it comes out the other end just as fast. Fitting the biggest exhaust pipe you can find may make your car sound great, but this can actually compromise the performance. Engines require a certain amount of back-pressure to function well, so it's a matter of getting the balance right. Exhaust manifold: Exhaust exits each cylinder via small pipes, and depending on the configuration of your engine these combine into one, two or more larger versions. The resulting tangle of metal pipes can make it difficult for the gas to flow smoothly and freely, and a replacing this with performance exhaust manifold will aid the flow. Exhaust pipes: An exhaust pipe needs to be matched to an equally decent manifold for it to yield the largest gains in performance. This final part of the exhaust system is designed to reduce sound and pollution (if a catalytic converter is fitted) and have a variety of filters and chambers to help achieve this. 'Cats' remove poisonous chemicals such as nitrous oxide and sulphur dioxide, mufflers deaden the noise but both sap precious power. If your conscience allows it, removing both of these elements can provide a few additional horsepower. A good 'straight through' stainless steel pipe combined with an optimised manifold can be an easy and worthwhile investment. Electronics: Electronics ECU upgrade / remapping One of the beautiful things about modern engines is the computerised control of almost every function, and even 20 year old engines will have some level of computer control over. 'Computer' is also a slightly misleading term, the hard work is done by relatively simple computer chips or Electronic Control Units (ECUs). ECUs have their preset parameters (or maps) hard wired into them by the factory and this is one of the ways that car manufacturers can change the character of an engine which is shared between many cars. Again, the mapping is the result of a compromise between emissions, economy, and performance and an ECU upgrade / remapping an existing ECU can be an easy performance gain. An ECU upgrade in a modern car can affect the following parameters: Spark timing relative to the piston position Electronic injection mixture Rev limit Valve timing Throttle progression Idle speed Forced induction How does a turbo work? A turbocharger is essentially a high pressure pump which forces air into the engine, more air means a bigger bang and more power, simple! The pump is essentially a rotating fan, which is powered by the pressure of exhaust gas. This is a beautifully simple setup but has one major disadvantage - you need exhaust pressure before the turbo will spin up to a useful operating speed, and need to get the engine revs up before you see the increase in performance. This phenomenon is known as turbo-lag and means the power delivery can be much less linear that normally aspirated engines. Considerations before fitting or tweaking a turbo Turbochargers are an easy method of dramatically increasing the power of an engine, and if you already have a turbo fitted you may be able to extract even more power from it. Be warned though, many engines are built strong but some not so - getting turbo settings wrong will compromise your speed by way of a small explosion. A quick Google search will reveal whether your engine is suitable for a turbo, and if you're lucky there may already be some after-market kits which have been tailored to your car. Intercooler Turbochargers produce a huge amount of heat due to the high speed of operation added to the fact they are powered by hot exhaust gas. The air which leaves the turbo will be at high pressure but also very hot and herein is the problem. Hot air expands which means there is less oxygen in any volume of hot air than the equivalent volume of cold air, less oxygen equals less bang which is lost power. An intercooler takes the hot air from the turbo and cools it in the same way as a car radiator, the air then contracts and you have more efficient combustion. Turbo modifications If you're lucky enough to have a turbo already fitted to your car, there are several things you can do to improve the performance. Most factory fitted turbos are set at a conservative level of boost by the manufacturer to reduce stress on the engine and provide increased durability. However, there are many engines which can withstand additional boost and operative reliably. Consult an expert to know if your engine is suitable for modification. The secret of increasing power via the turbo is to ensure the correct fuel to air ratios are maintained while increasing boost pressure - if you're pumping in more air you need more fuel too. At first, it's usually safest to increase the pressure by only a few PSI. The software on most modern vehicles will be able to adapt to this level of increase and deliver increased fuel to compensate. The methods involved with increasing boost pressure are varied, and you'll almost certainly need a professional to do this for you, but the technique is outlined below. The basic boost pressure is maintained by the waste gate which is designed to open at set pressures. Adjusting the waste gate to open at higher pressures is probably the easiest method of increasing boost. If you're looking for more power, you'll need a specialist to tweak the injection settings. ====================================================================== # Track preparation URL: https://www.drivingfast.net/track-preparation/ Category: Track Preparation for your car: Maintenance Driving a car hard on the track puts a great deal of additional strain on your machine so some simple maintenance is essential: Brake fluid should be relatively new as it tends to absorb water from the atmosphere - this can boil when the brakes heat up leaving compressible steam in the brake pipes which will cause spongy brake feel and reduced efficiency. Make sure oil, water and other fluid levels are topped up - cornering force can cause the build up of fluids on one side of the reservoir which can lead to fluid starvation. Have a look at the wear levels of brake pads and discs, and keep a spare set of pads handy if necessary. Check the tyre tread depth to make sure you'll have enough left after the wear and tear of track use. Finally, have a quick check round to make sure all the nuts and bolts are nipped up, especially wheel nuts and ensure any safety equipment such as roll cages and straps are securely fastened. Fuel Many drivers use a higher octane fuel when competing or attending track days - these fuels give more bang for your buck and can aid performance but tend to be more expensive. Don't brim your car when fueling - leave just the right amount to see you through the day. Excess fuel is heavy and can be detrimental to lap times - it can also slosh around if you don't have a baffled tank, causing unnecessary weight transfers which unsettle the car. Tyre pressures If you only do one thing before a track day, try to get the pressures right If you only do one thing before a track day, try to get the pressures right. This is a bit of a dark art, and many drivers are secretive of the pressures they run. At the very least, match the manufacturers guidelines, and as a rule of thumb, increasing by 5-10% should provide a better turn in and be generally more suited to track conditions. Experiment here, and take notes - eventually you'll find pressures which will give you a good compromise between grip, predictability at the limit and turn in. Pressure increases with temperature, so bear this in mind if you'll be doing a large number of laps - if you're doing short runs, you can probably get away with slightly higher pressures. Rubber compounds also tend to get softer and provide more grip as they get hotter (up to a point). So ensure your tyres are warm before attempting full racing speed. Take everything out! This should really go without saying but take out everything including the spare wheel, jack, luggage, coins, rubbish, children, seats etc This reduction in weight can make the difference between winning and losing. In addition, you don't want things rattling around while you're trying to concentrate, and in an accident anything that's left in the car is likely to hit you on the back of the head. Remove obstructions from the radiator If you're doing sustained laps, you'll need all of your car's cooling ability. If you have a turbo-charged engine, you'll probably have several radiators and intercoolers, all of which need a steady supply of air. Some cars have number plates which partially obstruct the radiator's precious air flow, so remember take these off to give a bit of extra cooling. Warming up the car It makes sense to get your car up to operating temperature before you start driving it hard - this will thin out the oil and let the engine expand and free up, which will make it more efficient and place less strain on the moving parts. Keep an eye on the water and oil temperatures to make sure the extra load isn't causing it to overheat. Driving position When getting ready for the track you should adjust your seat to a much more upright position than you may use when driving on the road. You should be able to rest your wrists comfortably on the top of the steering wheel while keeping a slight bend in your arms. This may mean moving closer to the wheel than you normally would which can feel strange at first, but will give you maximum control. Preparing yourself: Shoe choice Shoe choice is very important when driving quickly. You need to have good pedal feel, and to be able to press the pedals confidently and accurately. A racing shoe / boot is the best bet, which have very thin soles with no overhang. Second choice would be a thin soled trainer. Protective clothing Even if it isn't specified for the event you're attending, it's a very good idea to wear a helmet and fire retardant clothing such as a racing suit. Crashes happen, and you'll need to be able to walk away smiling. Walk the track The best way to familiarise yourself with the corners and the racing line is to walk the track first and picture where your braking, apex and turn in points could be. Also check for dangers such as corners with little run-off and anything else which might help you when you're in the driving seat. Mentality It's very common to get nervous / excited before an event, but you can't let this go to your head. Ease into it, find the racing lines and braking points, and gradually build up speed. It's very common to go off on the first lap, so don't let it happen to you. Enjoy! ====================================================================== # Wet versus dry driving URL: https://www.drivingfast.net/wet-versus-dry-driving/ Category: Track The first thing to think about is the decrease in friction between the contact patch and the road. This means you'll need to brake earlier, corner at a lower speed and squeeze on the power in an even more progressive way. In general, slow down or you risk sliding off the track. On a one mile track, the difference between wet and dry times can be as much as five to ten seconds. Approximate coefficients of friction (roads) with a multi-purpose tyre are shown below: Dry : 0.7 Wet : 0.4 For slicks, the difference is dramatic: Dry : 0.9 Wet : 0.1 Braking with locked wheels On dry roads, the stopping distances which can be achieved when braking with locked wheels vs threshold braking are relatively minor. However in the wet, if you lock up the wheels there is a much more dramatic reduction in friction which can lead to you ploughing ahead on entry to a corner. If you do lock up wheels you'll suddenly wish you had ABS, but if not now is a good opportunity to practice your threshold, cadence or avoidance braking techniques. Tyre pressures and grip Lower tyre pressures will increase the size of the contact patch, so letting some air out (while adhering to manufacturers guidelines) will allow you to gain a small grip increase in wet conditions. This will only help up to a point though! Tread depth and braking distance Recent research at MIRA (UK) measured the stopping distances at 50 mph in conditions that represented moderately heavy rain (0.5mm to 1.5mm water depth). The research discovered that tyres with a 3mm tread had a 25% better performance than those at 1.6mm. This represents an extra 8 metres (25ft) added to the stopping distance in wet conditions. In one test, when a tyre with a tread depth of 8mm was compared to one with only 1.6mm, the stopping distance increased by 13 metres (42.25ft). So the moral here is if you are considering a separate set of wet tyres for track use, try not to use them for everyday driving and make sure the tread is over 3mm deep. ====================================================================== # Advanced driving courses URL: https://www.drivingfast.net/advanced-driving-courses/ Category: Road A quick search on Google will reveal countless organisations which claim to provide 'advanced driving' courses. But what constitutes an advanced driving course, and what can you expect to learn from them? We've split the available courses into four broad categories, as shown below: Road / defensive driving focused Car control focus Track techniques Race craft ...or a combination of the above Road biased / defensive driving courses Example topics covered Attitude to driving Observation and reading the road Reacting to other road users Safe, smooth driving techniques Road biased courses tend to concentrate on making progress on the public roads while reducing the chances of an accident. In the UK, the basis of most courses is a system of defensive driving originally developed for police drivers called 'roadcraft'. As a result, many of the instructors who run these courses are retired police drivers. This system of driving has a proven track record for safety and is especially useful for drivers who haven't learned any track-based techniques such as heel and toe shifting. Good defensive driving courses: Institute of advanced motorists (IAM) RoSPA Car control focus Example topics covered Understeer Oversteer Braking technique Smooth driving For the purposes of this article, 'car control' means controlling the car at or near the limits of grip. Before embarking on any advanced course, drivers should at least be confident in the use of the basic controls of the car! Courses with a car control focus are often the most fun, and incredibly valuable before learning to drive fast on the track. They are usually based on a large area of open tarmac or on specialist facilities such as skid pans, or low friction surfaces. When the limit of grip is exceeded on the road, understeer or oversteer usually results, and plenty of the course content will be dedicated to controlling these situation. The skills you'll learn also transfer to certain situations on the road, for example when encountering an icy patch or having to brake hard to avoid an unexpected hazard. Track techniques Example topics covered Racing line High speed cornering Heel and toe Front versus rear wheel drive techniques Track based techniques can be taught equally well in a sports, racing or road car but here the emphasis is on speed. Learning the racing line is a crucial element to successful track driving and you're likely to experience some demonstration laps to give you an idea of what's required. Braking, apex and exit points are often marked out with cones and an instructor will usually sit with the driver throughout the course. Racing is usually not encouraged, but overtaking is common for the faster drivers. Race craft Attacking / defensive lines Overtaking Mechanical sympathy The winning mentality These courses build on your track driving skills and teach the techniques to successfully race other cars. These courses often use high performance karts rather than cars (for obvious reasons) but the techniques you'll learn are transferable to any car. There is often a certain amount of theory to learn, so expect to sit in front of a whiteboard for at least some of the day. You should come away from these courses with a number of specialist track skills which will be useful if you indent to compete in motorsports. When choosing an advanced driving course, make sure you understand the course content and learning outcomes to avoid disappointment on the day. Look for customer reviews online to ensure you get a reputable company, and have some objectives in mind to help the instructor shape the course to your requirements. Have fun! ====================================================================== # Driving in floods URL: https://www.drivingfast.net/driving-in-floods/ Category: Road Firstly, it's important to note that driving through a flood can be very damaging to your car, terminal even. Secondly, there is a very real possibility of being killed if you get it wrong - people die every year doing this. So, perhaps it's better to find another route don't you think? If you're not phased by this warning, by all means read on... Or read this special guide to wading for those lucky enough to own a 4x4 The boring recce & preparation bit So, it pouring with rain outside, it's late, and you desperately need to get to your mum's house so she can wash your pants. But then you turn a corner and the road is completely covered by water. Before diving in heroically, it's best to check a few things. A. First, mentally note how similar a car is in design to a boat. A boat In fact, the best vehicle for floods is the penny farthing, which isn't at all boat like. Look at these two nice chaps having a wonderful time. Not at all phased by the weather. Two penny farthings A car is cleverly sealed from beneath to prevent water ingress and this means in a worryingly small amount of water it will become buoyant - you won't be able to steer particularly well, and you'll float in the direction of the current into the nearest tree or ditch. Eventually water will seep in and you'll get your feet wet. Take a look at this short clip to prove the point - note that the water didn't even cover the rear bumper before it started to lift off the ground, albeit in unusual circumstances. As a very vague rule of thumb, if water is half way up the wheel rim, there is a good risk of vehicular floatage. Your owners manual may or may not quote a maximum wading depth - heed this advice is you're the advice taking type. B. Check for hidden obstacles. This may seem slightly impractical as it's unlikely you have your fisherman trousers on, but this is quite important to do this if you don't like high risk activities. Take a look, or better still get in there with a long stick and prod around - look for shopping trolleys, otters and most importantly missing drain covers - these can easily swallow a wheel and make it impossible to progress. If you don't feel like getting wet, why not park up and watch somebody else attempt to drive through, if they disappear under the water tiptoe back to your car and turn around. C. Have a think about your car, especially the location of the air intake. Some cars are just not cut out for wading, but if you have an air intake which is nice and high you have a slightly better chance of success. If water is sucked into your engine, the pistons will try and compress it, but water cannot be compressed - it's actually stronger than metal in this situation and it will break something very important in a catastrophic and noisy way. Sometimes the entire engine head can be blown off, or you can bend a con rod. A bent connecting rod D. Consider your position in the road. Surfaces are usually higher in the middle to aid drainage - drive here to give yourself the best chance of success. If the water is shallow enough for two cars to pass, time your run to avoid passing a car coming in the opposite direction - their bow wave can easily flood your engine and make you very angry. Avoid the edges of the road as it can be hard to detect where the ditches start. E. If the water is flowing, avoid it. It's just too risky, it won't work, you'll regret it in the morning. The fun driving bit When attempting to drive into the flood and out of the other side, do the following: Be slow. Walking pace or slower is usually ok. Use first gear, and if you need to slip the clutch to keep your speed down that's fine. If the water gets deeper and a small wave forms in the front of your car this can help artificially lower the depth of the water in the engine bay, which isn't a bad thing. Don't worry too much about water getting into the exhaust, this won't happen as long as the engine is running. If you do stall due to driver error - make sure you restart as quickly as possible to avoid water being sucked up as the air in the exhaust cools. Concentrate on keeping a steady speed and maintaining momentum. If you stall for an unexpected reason water may already be in the engine, it's up to you whether to try and restart but it could do more damage. If the water gets deeper unexpectedly, you should have done a better recce! Slow down as you reach the other side - you don't want water coming back towards you and going over the bonnet. Test your brakes if you're feeling safety conscious, although they will usually be absolutely fine unless you're in a Model T Ford. Modern discs work pretty well even under water. If you've floated into a deep river and sunk If you do find yourself sinking to the bottom of a pond - here's a simple guide to escaping from your car unscaithed. Undo your seatbelt. Surprising how many people forget to do this. Must be the impending doom. Whether you like it or not, you're going to get wet. You won't be able to open the doors due to the water pressure. If you're a cheapskate and bought a car without electric windows you've had the last laugh - roll them down smugly. If you're lucky enough to have a car with electric windows they probably won't work any more - you need to smash the window somehow. You could use a tool like the one below, or punch through like a real hero. Once you're under water even a hammer won't help as you won't be able to get the necessary speed up. If you fail to break the window, water will fill up the car anyway. Calmly wait for it to be completely full, and take the time to remember how good your life has been so far. Once the car is completely full, you'll be able to open the door and swim gently to the surface. Image credits: Stock images provided by freedigitalphotos.net. The boat is by Dan, many thanks.. ====================================================================== # Everyday driving tips URL: https://www.drivingfast.net/everyday-driving-tips/ Category: Road Braking - smooth and progressive Progressive application of the brakes is vital to maintain stability and composure at speed Progressive application of the brakes is vital to maintain stability and composure at speed. To do this, press the brake pedal until contact is made between the brake pads and discs (i.e. take up the slack), then squeeze on the pressure until the required rate of deceleration is reached. This doesn't mean you can't brake firmly or quickly but it's important to make the application progressive rather than simply stamping on the pedal. Equally important is the smooth release of the pedal. Remember you can brake much faster than you can accelerate thus the weight transfers while braking (and easing off the brake) are more extreme. Progressive braking will make you less likely to lock a wheel or lose control due to loss of traction. Acceleration - squeeze on the gas No matter how much (or little) power your road car has, you can practise progressive acceleration, although the benefits will be more dramatic in more powerful cars. Applying the throttle too early or too aggressively can lead to unwanted weight transfers and spinning wheels. Steering Steering position should be at the nine and three o'clock positions, as this is the position which gives you a good range of motion without forcing your hands off the wheel. Adopting this position will allow you to turn the vast majority of corners without shuffling hands or taking one off the wheel. Allow both hands to do the work - don't simply pull with one or push with the other, splitting the effort will allow you greater control and give you more feedback from the road. Gear changes Changing gear is often overlooked but is often where the greatest gains can be made Changing gear is often overlooked but is often where the greatest gains can be made. Rev-matching and heel and toe should be second nature for anyone changing down in a manual transmission car. When making any gear change, the shift should be imperceptible from the passenger seat as in extreme cases, dodgy shifts can lock wheels of cause wheelspin any any loss of traction means you're losing time on the track. Don't use the gears to slow you down, modern brakes are very good at doing this for you and give you a much greater amount of control, if you do decide to change down before a corner this should be done to give you maximum acceleration on the way out, not to slow you down on the approach. Finally, when changing down before a corner, ensure you brake first then change down - this will get the engine speed down to a point where the gear change is easier to perform smoothly. Weight transfers Avoiding dramatic shifts in weight due to aggressive driver inputs is vital for every performance driver. You may be able to get away with this behaviour at lower speeds, but as soon as your car approaches the limits of grip even a tiny weight transfer in the wrong direction can cause you to lose traction. Practising smooth driving every day will make the journey more pleasant for your passengers, but also allow you to cover the ground more quickly and safely. That's all for now - happy motoring! ====================================================================== # Improve fuel economy URL: https://www.drivingfast.net/improve-fuel-economy/ Category: Road Let's face it - fuel is getting more expensive and we can't drive everywhere like a lunatic. So how can you make the most of your hard earned gas? Let's start with the simple stuff... Keep your car well maintained Following the correct service intervals will keep your car running efficiently. New air filters will allow the free flow of air necessary for efficient fuel combustion, clean fuel filters provide a steady stream of petrol to the cylinders, and shiny new spark plugs will provide the spark needed to set the whole thing off. A thing of beauty! They key here is the efficient burn of the fuel air mix, which will allow more power to be extracted from a set volume of fuel. A new air filter alone could reduce your fuel consumption by up to 10%. Tyres Under inflated tyres need more energy to roll. Keeping the pressures at the correct level can increase economy by up to 3.5%. Specialist fuel saving tyres are also available, although these may not perform so well on the track! Properly inflated tyres are also key to providing optimum levels of grip, so it's worth checking periodically. Gears Using higher gears won't give you lightning acceleration but will save fuel. Keeping your revs low (but not so low that your engine starts to struggle) is a good habit to get into when cruising. If you have a "Sport Mode" on your auto transmission, turn this off, as this will hang onto low gears for longer and may even prevent changing to the highest cog. Accelerate hard to save fuel?! A British automotive engineering consultancy claims to have unearthed proof that putting your foot down hard on the accelerator can actually be more fuel efficient than driving more conservatively. “It sounds totally counter-intuitive — and it is,” admits Cousins. The key to saving fuel, he says, is to accelerate hard until the engine reaches 2000 rpm, move up a gear, then put your foot down until you reach 2000 rpm again. It’s all to do with internal friction. “Put simply, with your right foot down on the accelerator, the engine is working at its most efficient,” says Cousins. Above 2000 rpm the benefits diminish and you start using more fuel, not less. Here’s the really interesting thing: in tests carried out in a Citroën C1, one of the most fuel-efficient cars, Cousins’s driving technique proved 8.5% more efficient than the “eco-safe driving” style promoted by the Department for Transport (http://www.dsa.gov.uk — search for eco-safe). The government’s official driving method — taught to all UK learner drivers and now included in the driving test — encourages drivers to save fuel by using the accelerator pedal only lightly. Source: driving.timesonline.co.uk Dr Steve Cousins should know what he's talking about - he was project leader for the Axon Automotive Caterham 2R which achieved 131 miles per gallon in UK Shell Eco-marathon, and is one of the world's top researchers into fuel economy. Accelerate gently to save fuel Although there may be evidence that accelerating hard to 2000 rpm could save you fuel, accelerating to the red line in every gear will certainly not. In general, try to keep a constant speed where possible by judging potential reasons to slow down in the road ahead and react to them, avoiding rapid changes in momentum. If you're slowing down and accelerating the whole time, fuel bills will go through the roof. Speed The faster you go, the harder it is to propel your vehicle through the air. This means that a small decrease in cruising speed could provide fuel economy benefits. The UK's Department of Environment claims that every 5 mph you drive over 65 mph will provide a 7% decrease in fuel economy. ====================================================================== # Snow & ice driving myths URL: https://www.drivingfast.net/snow-ice-driving-myths/ Category: Road Myth 1: ABS is a bad thing in winter conditions Anti-lock braking system It is true that when ABS is operating in slippery conditions, your stopping distance is likely to be increased. However, ABS prevents wheel lock-up and allows you to continue to steer effectively rather than sliding out of control - and this is usually beneficial when trying to avoid obstacles, people and other cars in an emergency braking situation. It's very unlikely that you'll be able to disable ABS in a modern car so it's best to learn how to use it effectively, understand its limitations and accept that it's a well proven safety system that could save your life. Click here to learn more about ABS systems Myth 2: You should turn off traction control when it snows Traction control Most traction control systems (such as ETC, DSC, ESP) can reduce engine power or apply the brakes in response to spinning wheels. When driving in winter conditions, it is especially beneficial to keep these systems active as they are much more capable of maintaining traction (and keeping you on the road) than most humans. However there are occasions when a reduction in power can hinder progress (for example when stuck in deep snow), and only then should these systems be temporarily switched off. If you have tried pulling away unsuccessfully - try turning the systems off and having another go. If this doesn't work you'll need to consider your options. Click here to learn more about traction control systems Myth 3: A lower gear is better in slippery conditions Gears Pulling away When pulling away in slippery conditions, selecting the lowest possible gear is usually not the best option. Lower gears provide more torque at the wheels and this extra twisting force is more likely to cause wheel-spin and prevent progress. Selecting the highest practical gear reduces torque, and gives you the best chance of success. Pull away with a light throttle for best results, and keep in a high gear especially when climbing hills. Driving down slippery hills When descending a slippery hill, the engine braking generated while in a lower gear can be very helpful. Using the brakes encourages the wheels to lock, whereas engine braking helps reduce speed while keeping the wheels rotating - this can help prevent wheel lock-up and maintain your ability to steer without having to resort to ABS. While cruising When cruising you need to strike a balance between the ability to call upon engine braking when necessary (when lifting off the throttle) and keeping the chances of wheel-spin to a minimum. In this case a compromise is needed and a gear which maintains an engine speed of between 2000 and 3000 rpm is a good rule of thumb. Myth 4: Cadence braking is a useful technique in modern cars An illustration of cadence braking Cadence braking is the process of rhythmically applying and releasing the brakes in order to get a compromise between steering and braking performance. However this technique is only useful in cars without ABS fitted (ABS performs a similar process, but much faster and more accurately). If you need to emergency brake in modern vehicles, the best results are achieved by pressing the brake pedal firmly and keeping pressure on the pedal until you have come to a halt. Click here for more information on braking technique ====================================================================== # Winter driving tips URL: https://www.drivingfast.net/winter-driving-tips/ Category: Road Winter conditions can be unpredictable, however most of the techniques required in cold environments are common sense. Rules of thumb Keep speed as low as practically possible Increase your distance between cars Slow right down for corners, junctions and any other hazards If travelling long distances, be aware of changing conditions along your route Get all of your braking done on the straights, never brake during a corner if it can be avoided Be prepared for understeer and oversteer, and know how to correct when necessary Be prepared to use ABS or avoidance braking techniques Top up washer fluids and antifreeze Select 'snow' mode if available on automatic transmissions, or if an advanced electronic stability control system is fitted If you have to climb a slippery hill, ensure the top is clear before starting the ascent Use a good snow forecast app and be prepared Many websites have published information which deal with the above issues well, so if you need more of the basics, try a Google search. This article discusses some more advanced safety-based techniques for making progress in winter driving conditions. Are you a 4x4 owner? Read our dedicated article specially for you Introduction to winter driving techniques Making the most of available traction is key to winter driving Making the most of available traction is key to winter driving. Loss of traction can lead to wheelspin under acceleration, wheel-lock under braking and sideways sliding while cornering. There are many automatic stability control systems which can control these actions to a limited extent, however there is no substitute for the correct technique. Investing in a vehicle with ABS is the single most effective method of increasing your safety in slippery conditions, and luckily most modern cars have this as standard. Traction control systems can control wheelspin, but bear in mind that these technologies are reactive, which means you will already be in a certain amount of trouble before they start to operate. It's much better to avoid the problems to start with, and this is where technique comes in. Top tips for driving on snow and ice Pull away and accelerate gently and progressively In slippery conditions such as snow and ice, aggressive acceleration is likely to break traction at the driven wheels. The resulting wheelspin can lead to loss of steering control in a front wheel drive (FWD) car, or an oversteer slide in a rear wheel drive (RWD). Both of these situations will prevent you from going in the direction you want and can be difficult to recover from. Quickly recover from wheelspin If you do notice wheelspin or the traction control systems fighting for grip, fight the urge to floor the throttle, and instead back off the gas and then re-apply smoothly. keep the engine speed (rpm) as low as possible Keep a constant low throttle in order to maximise grip. Most diesel engines will cruise along happily in low gears without using any throttle as all. Reduce torque at the wheels Change up sooner rather than later, pull away in second gear if possible, and use the highest practical gear at all times. Higher gears reduce torque at the driven wheels and therefore lower the chances of wheelspin - especially important if you need to climb a slippery hill. Keep gear changes as smooth as possible, as it will be easy to spin the wheels in most gears when conditions are really challenging. If you drive an auto, make use of any winter settings at your disposal. Avoid sudden driver inputs These can include steering, braking, acceleration or gear changes. You only have a finite level of grip available so try not to overload your tyres unnecessarily. Driving smoothly will conserve grip, and make you safer on the roads. Brake soon, and gently If you do not have ABS fitted, be prepared to ease off the brakes when necessary to steer more effectively. Locked front wheels cannot steer! Make the best use of ABS If you do have ABS, you'll be able to tell it has triggered by feeling a pulsing sensation through the brake pedal. If this has occurred do not 'pump' the brakes, rather keep a firm pressure on the pedal for maximum effectiveness. ABS is designed to help you steer as you're slowing down so use this to your advantage and avoid obstacles. Prevention is better than cure Even if you do have ABS or traction control systems fitted, don't get into the habit of using the technology routinely, you'll be able to slow down in a shorter distance if you use threshold braking techniques. Use a trailing throttle through corners Easing off the gas before you enter a corner will transfer some weight to the front wheels, helping to increase traction where it's needed. Carry speed up slopes Demands on your tyres increase dramatically up hills. You need to carry a suitable amount of momentum to make it to the top. As you do approach the brow of the hill, ease off the throttle and come to a gentle halt. Control speed down slopes Keep your speed down from the top of a hill, don't expect to be able to scrub off much speed on the way down. Think well ahead and prepare for the next hazard. Observation and anticipation No matter how skillful you are, there's no substitute for thinking ahead. If you're in familiar areas, anticipate what's coming up, and if you're not in a place you know well, then expect hazards around every corner. Learn how a car behaves at the limit of friction This is a sensible idea for any driver - go to a skid pan or play around on a track. Spin a lot, learn how to control slides, this is such a helpful transferable skill which may save your life one day. Recovering from slides in very slippery conditions If you're an experienced driver you may be able to use other techniques to help recover from these situations, and these are covered in the dedicated oversteer and understeer articles. Article on oversteer Article on understeer Understeer is when you turn the steering wheel but find that the car has a tendency to continue straight ahead (Figure 1). Oversteer is when the car tries to spin round due to a lack of traction at the rear (Figure 2). Both situations are more likely on winter roads but can be helped using the same techniques (which should make things easier to remember). Figure 1: Winter understeer - the car continues straight ahead despite applying steering lock Figure 2: Winter oversteer - the rear of the car breaks loose and a spin is likely if not corrected Resist the urge to stamp on the brakes during understeer or oversteer, as this can make things much worse If you do find yourself in an understeer or oversteer situation on a very slippery road try not stamp on the brakes in panic as this can make things worse. Instead, smoothly ease off the throttle and keep the steering pointing in the direction of intended travel. Rapid or harsh driver inputs of any kind should be avoided. You also need to try and get the driven wheels turning at road speed to regain maximum traction. Press the clutch or flick an automatic into neutral to remove the influence of the engine and help get the wheels rotating at a more natural rate. With luck, this will create vital grip to avoid obstacles and allow you to progressively apply the brakes. When traction is regained, be prepared to take off the steering lock quickly in order to prevent another slide in the opposite direction. Now apply the brakes smoothly and work out what to do next. Cars with electronic stability controls fitted An example stability control indicator light Modern traction control systems will make the best use of available grip Most modern cars are fitted with electronic stability control systems which can be very helpful in slippery conditions. These technologies all work in roughly the same way and have two main methods of intervention: Reducing throttle Applying brake force to individual wheels The quality of these systems do vary, but most can react very quickly and apply more precise corrections than most drivers can manage. Once stability control is activated, all the driver really needs to do is keep the steering pointing in the intended direction of travel and apply the brake when needed. The only time you may want to think about turning these systems off is when the car is struggling to travel in deep snow, or as a last ditch attempt to pull away in extremely slippery conditions. Dedicated article on stability control systems Tackling slippery hills Ascent Climbing a hill successfully requires the right balance of traction and momentum. If you lack traction, you'll need more momentum, but momentum creates it's own difficulties - it's a balance of finesse and bravery. To climb a slippery hill, you need to carry speed - build it up at the base of the hill as accelerating mid way is rarely any use. Before you attempt a climb, it's very sensible to have somebody at the top of the hill to signal when the coast is clear, and to warn approaching cars to stop. Reverse to gain sufficient run up, and once on the hill keep a steady throttle - resist the urge to accelerate mid-way as this will likely kill your traction and cause wheel spin. Ease off the throttle towards the top of the hill. Probably best to have a go slowly first, then build up speed if required. If you do fail to make it to the top, quickly select reverse, keep off the gas and steer your way to the bottom for another go with more gusto. Descent Again, it makes sense to position somebody at the base of the hill to warn other traffic. Once you're on the hill, it can be impossible to stop and you'll need some run-off room too. Select first gear, ease over the crest then keep your feet off the throttle and control your speed gently with brakes if required. Engine braking is your friend as it resists wheel lock. If it's very very slippery, even first gear can provide too much braking and the car will start sliding forward - if this is the case, you can try momentarily accelerating, then easing off the gas to try and regain steering control, but this is a fairly advanced technique which requires practise. Stopping distances in varying winter conditions Finally, we'll take a look at stopping distances to emphasise how important it is to slow down and brake early. Graph 1 shows the dramatic difference in braking distance when on black ice compared to normal tarmac conditions with the same tyre, it's well worth bearing this in mind in the winter an adjust your driving style accordingly. Graph 1: Stopping distance vs speed for dry asphalt and black ice Source: csgnetwork.com/stopdistcalc.html Friction levels in different winter conditions Graph 2 below summarises the levels of friction available in different winter conditions - the worst conditions observed provided only approximately a quarter of the grip of dry asphalt. Graph 2: Grip levels in different conditions (calculated as the coefficient of friction) Source: John E Hunter (1998) Society of Accident Reconstructionists Winter tyres The difference winter tyres make is remarkable Depending on the severity of the conditions, it may be worth considering specialist winter tyres. The difference they make is remarkable. These vary from a Mud and Snow (M&S) rating through to studded tyres for icy roads. Surprisingly, with the correct tyres fitted, driving in quite severe conditions can become simple - you just have to pay a visit to Finland or other northern countries in the winter for a demonstration. Note that studs aren't legal in some countries due to the damage they can do to road surfaces. Manufacturers of winter tyres use several methods to increase friction and help maximize control. Firstly, the rubber compounds are usually softer which allows optimum friction to be reached at lower temperatures (this however does make them wear faster when used in warmer conditions on dry tarmac). The diagram below shows the effect of different rubber compounds on the stopping distances in different temperatures. Secondly, winter tyres can have small 'sipes' which are formed into the rubber within a tread block - these provide grippy edges which are especially useful when driving in snow. Thirdly, the tread tends to be wider and deeper which provides more bite when driving in the snow or on ice. Sipes: the horizontal lines shown in the image Deeper tread provides more 'bite' Winter tyres usually also have an aggressive block-like tread pattern which can help to dig into the snow and provide traction (also useful in muddy conditions). Finally, small studs can be fitted to the tyre and these provide a great deal of benefit when driving in icy conditions, although in some countries these are only permitted in the coldest months as they damage road surfaces. Studded tyres can also increase your braking distance when on a clear dry road. Winter tyre performance WHATCAR? magazine tested a selection of winter tyres braking from 25mph to a complete stop in a VW Golf in 2012. The results, which are dramatic, are shown below. Driving in snow Winter tyre performance in snow Driving on ice Winter tyre performance in snow Snow chains If you're driving in deeper snow, it might be worth considering using snow chains, or at least having some in stored in your car. These are fitted to the driven wheels and can provide dramatic increases in traction. If you do choose to fit snow chains, ensure the manufacturer's instructions are followed carefully or damage to your car could result. ====================================================================== # Climbing hills URL: https://www.drivingfast.net/climbing-hills/ Category: Off-road Steep hills can be one of the trickiest obstacles you're likely to encounter while driving off-road. Not only have you got a gradient to contend with, but gravity is also working against you. It just doesn't seem fair. However, science is on your side - when attempting the climb for the first time, consider the proven formula for success: A successful climb = the correct route + sufficient traction + sufficient momentum. Rules of thumb High / Low Range : Low Gears : Select the highest practical gear if slippery Suspension : Raise if necessary Diff lock(s) : Engage Speed : Momentum may be needed, but ease off at you approach the top Note : Be prepared for failure and know how to recover from it Choose the correct route The route you pick depends on a number of factors which can be influenced by the following: Obstacles such as trees or rocks The presence of existing tracks Ruts Tricky 'no go' areas (such as slippery or difficult ground conditions) The rule of thumb when climbing hills is to attack the slope using a route which minimises any side angles where possible. If you start to slide sideways you'll have very little control over your vehicle, but sliding forwards or backwards can be controlled. Diagram 1: Driving straight up the hill is the safest route, as it minimises side angles Diagram 1: Climbing a hill off-road However, if you're driving in a rutted track it can be best to stick to the exiting route. If your wheels are positioned in the ruts it's very unlikely that a sideways slide will occur. Diagram 2: If you're driving in a rutted track, sliding sideways if unlikely so it's best to stick in the ruts. Diagram 2: Climbing a hill in ruts Technique for climbing steep hills [manual transmission vehicle] Recce the route on foot - ensure it's safe to climb, and consider the consequences if you fail half way up. The less grip there is available, the shallower the angle you'll be able to tackle. Once you're back in the car, hold the car stationary on the foot brake. This acts on all four wheels, and has power assistance, unlike the handbrake which tends to act on the rear wheels only. Select a suitable gear for the surface - if the surface is slippery, higher gears provide less torque and thus more traction in slippery conditions. If you're on a high grip or uneven surface a low gear may be a more sensible choice as it will provide maximum control at low speeds Set the throttle - don't rev the engine, but select engine revs which allow the engine to exploit the power band (3000 rpm is a good guide) Progressively release the clutch and do a test run - attempt to climb a few meters of the hill to determine how slippery it is. If you're getting a lot of wheelspin then you'll need a fair amount of momentum to complete the climb. If it's too slippery, perhaps now is the time to find an alternative route. If there is sufficient grip, attempt the climb using a run on the flat is necessary. Be prepared to recover from failure (technique described below). If you start to slide backwards, follow the techniques explained here Failing to climb If you've failed to make it to the top, the chances are it's either because of one of the following: Lack of grip - if there isn't enough friction available between the tyre and the ground surface to get you to the top, you're going to need more momentum. More speed, however means more danger so make sure you're confident about your decision. Lack of momentum - if you fail to get to to the top due to a lack of momentum, you're likely to stall or simply run out of steam and may even stall the engine. If you do stall, don't panic and hit the clutch, but follow the guide to recovery shown below. Recovering from a failed hill climb due to lack of traction or momentum (manual transmission with the engine still running): Press and hold the brake pedal firmly Look behind you and make sure the coast is clear Engage reverse gear Release the clutch to the point of bite Swiftly but smoothly take your foot off the brake, fully release the clutch, and allow engine braking to slow your descent (avoid the brakes) Follow the line which minimises any side slopes - keep the vehicle straight Determine whether it's safe to have another attempt Attempt the climb with more speed, using a run up if necessary If the slope if so slippery that the wheels are locking due to engine braking - you may need to gently apply some throttle to regain traction, then release the throttle gently to re-establish braking. Recovering from a failed hill climb due to engine stall (manual transmission): Hold the vehicle using the foot brake Check to see if anyone noticed - this could be embarrassing! Clutch in and select reverse gear (engine is still off at this point) Release clutch and gently release the foot brake Now the car will be held on the slope purely by transmission, and may start to move backwards if the slope is very steep Check behind you then restart the engine while in gear (this will ensure engine braking operates from the moment you start to move) Avoid using the brakes and reverse down the hill using engine braking for another attempt. Recovering from a stall in an automatic transmission: It's unlikely that you'll stall an auto, but it can happen. If this does occur, hold the foot brake firmly and restart the engine (you'll probably need to select N or P first). Now follow the stages shown below. Recovery due to lack of traction or insufficient traction or momentum in an automatic vehicle: Press and hold the brake pedal firmly Look behind you and make sure the coast is clear Engage reverse gear Smoothly take your foot off the brake and allow engine braking to slow your descent Follow the line which minimises any side slopes - keep the vehicle straight and avoid the brakes Determine whether it's safe to have another attempt Attempt the climb with more speed, using a run up if necessary Diagram 3: Reverse down the slope to recover - minimise side slopes to increase safety Recovering from a sideways slide If you have no choice but to ascend the hill using a side angle, drive as slowly as possible using a light throttle and a high gear to reduce the chances of spinning wheels or a slide. Sometimes a slide is unavoidable and there will be a temporary loss of control. To recover from this situation, you need to heavy end first to allow gravity to help, rather than hinder: Do not hit the brakes or press the clutch - this may be your first instinct but will only lock the wheels or disengage the drive Steer down the slope to get the heavier front of the car pointing down slope If the front refuses to come round, try using some gentle throttle to assist the turn One the car is pointing downhill, ensure you are off the gas and allow engine braking to slow the descent Diagram 4: Recovering from s sideways slide (best avoided in the first place!) ====================================================================== # Controlling slides off-road URL: https://www.drivingfast.net/controlling-slides/ Category: Off-road If you're driving on slippery terrain, you can expect to slide from time to time. Controlling a slide is an important skill to master to ensure safety when off the beaten track. There are several types of slide you can expect to encounter: Driving uphill Driving downhill Driving on a side slope Driving on the flat Rules of thumb Don't panic (easy to say) Don't hit the brakes or clutch Use the techniques below to recover Driving uphill When attacking a slippery or steep slope, there a chance that although the wheels are turning forwards the vehicle will start to slip back. This can be expected from time to time and grip is usually re-established quickly, but if the car continues to slide backwards you'll need to take action. Press the brake and clutch* together - this will lock the wheels temporarily which will allow reverse gear to be selected. Select reverse Release the clutch (in amanual transmission vehicle) and brake Allow engine braking to take you to the bottom of the slope for a second attempt Keep the vehicle straight to avoid side slopes Driving downhill Controlling a forwards slide when pointing downhill can be difficult to do. Everyone's first instinct is to hit the brakes, however this rarely helps the situation as this makes the wheels more likely to lock (which will prevent you from being able to steer). If you are driving down a slope using engine braking and the wheels lose grip it's usually safest to try and steer round obstacles and come to a halt where possible. Sometimes a dab on the throttle can aid steering and help re-establish traction, but this should only be attempted when there is sufficient room. Driving on a side slope If you have no choice but to drive on a side angle, drive as slowly as possible using a light throttle and a low gear to keep the speed down. Sometimes a slide is unavoidable and there will be a temporary loss of control. To recover from this situation, you need to heavy end first to allow gravity to help, rather than hinder: Do not hit the brakes or press the clutch - this may be your first instinct but will only lock the wheels or disengage the drive Steer down the slope to attempt to get the heavier front of the car pointing down slope If the front refuses to come round, try using some gentle throttle to assist the turn One the car is pointing downhill, ensure you are off the gas and brakes, allow engine braking to slow the descent The correct technique to control a sideways slide Controlling a side slope slide Driving on the flat If you find yourself in a slide on the flat, chances are you're coving ground at a relatively high speed or traveling in low traction conditions. The two slide situations which can result are know as understeer or oversteer which are explained in detail below with a road bias, but the principles are equally relevant off the road. Oversteer explained Understeer explained ====================================================================== # Descending hills URL: https://www.drivingfast.net/descending-hills/ Category: Off-road When descending a steep or slippery hill, it's important to consider the consequences of losing traction and being unable to stop on the slope. If you're pointing directly up or down-slope it's relatively easy to control your direction even without the ability to stop, however if you start to slide sideways you're best course of action may be to close your eyes and wait for the crunch. Rules of thumb High / Low Range : Low Gears : 1st Suspension : Raise if necessary Diff lock(s) : Engage Speed : Tick over for maximum engine braking Notes : Avoid the throttle and brakes if possible Descending hills: The technique Stop well before the slope begins and get out of the car. Check the slope for obstacles and ensure you have a suitable run-off area in the event of complete loss of traction. Stick to existing tracks if possible (ruts will help prevent you sliding sideways). Select a gear which is suitable for the conditions and the severity of the slope. Low gears provide better engine braking, but may cause a loss of traction on particularly low grip surfaces. Engage any differential locks you have fitted, and turn on any electronic aids designed to help descents. Pull away, and ensure the clutch is completely released (if you're in a manual) before the slope begins. Ensure you are lined up correctly and your wheels are completely straight when beginning the descent. Do not touch the brakes unless you need to come to a stop - this will either trigger ABS, or make the wheels likely to lock which will mean you'll be unable to steer. Use engine tick over to ensure maximum engine braking, avoid using the throttle or brakes. If you start to slide, follow the techniques explained here Diagram 1: Descending a hill correctly ====================================================================== # Ditch crossing URL: https://www.drivingfast.net/ditch-crossing/ Category: Off-road Ditch crossings can be quite hard on your car unless the correct technique is used. There is a risk of contact with the ground, and loss of traction is fairly likely depending on the size of the ditch. Rules of thumb High / Low Rang e: Low Gears : 1st Suspension : Raise Diff lock(s) : Engage Speed : Engine tick over (unless there is a risk of stalling) Note : Cross at an angle, not straight What not to do: Crossing a ditch straight will cause both front wheels to fall into the depression simultaneously and for the front suspension to compress. This can cause the front of the vehicle to make contact with the ground, or reduce traction to the point where you might become stuck. Don't cross a ditch straight on Ditch crossing - straight The correct ditch crossing technique: To negotiate a ditch in a more reliable manner, cross at an angle, allowing only one wheel to enter the ditch at a time. This provides the greatest chance of success by maintaining the best possible traction using three out of the four wheels. Ensure all the traction aids at your disposal are engaged (such as traction control and differential lock). Tackle the ditch at a slow speed, but have sufficient momentum to drive the vehicle through. If you have the luxury of adjustable suspension, ensure the highest setting is selected to prevent any contact with the ground. Be prepared to increase the throttle slightly if wheels start to spin. The correct ditch crossing technique Ditch crossing - correct ====================================================================== # Driving in deep water URL: https://www.drivingfast.net/driving-in-deep-water/ Category: Off-road Wading though deep water can be one of the most enjoyable and exciting aspects of off-road driving, however it can also be dangerous and may damage your vehicle. Follow our guide below to minimise the risk and increase your chances of getting to the other side. Please note, this article is intended for those with a 4x4 vehicle and decent off-road driving experience. Rules of thumb Check your vehicle's maximum wading depth Recce the crossing on foot Consider the environmental impact Select a gear which reduces the chances of stalling Use a bow wave to artificially reduce the depth of the water Keep moving and don't let the engine stop Avoid flowing water unless you know what you are doing Check your maximum wading depth Wading depth is set by the manufacturer of your vehicle and is determined by a number of crucial factors. These include the location of sensitive electronics, the air intake, and other venerable areas. Often the manufacturer will assume you'll only be wading for a few minutes, so if you intend on regularly crossing rivers some additional preparation may be required. Consult an expert if you're considering a serious expedition. It's a good idea to have a reference point on the vehicle as an indication of the wading depth - usually the top of the wheel rim is a safe bet, but consult your handbook for more information. 4x4 Accessories The following accessories may be required for sustained wading in deep water: Wading plugs or breathing tubes for the gearbox and differentials to prevent water ingress Sealed air intake snorkel to prevent water entering the engine Radiator barrier to lower the water level in the engine bay Splash baffles can prevent the fan throwing water everywhere in your engine bay Preparation Disconnect or disable fans if necessary to prevent damage to the fan blades and reduce the amount of water thrown around inside the engine compartment. Ensure you have no fluid leaks which could be potentially hazardous for the aquatic wildlife. Pre-attach a tow rope to your recovery points if you think there is any risk of getting stuck - attach on the side of the vehicle you're most likely to be recovered from. Perform a recce to determine the best route. Recce If you are in doubt about your ability to cross, get out and walk the route (fishing waders come in handy here). Check the ability of the ground to provide traction and support and look around for hidden obstacles. Use a marshal if necessary to provide a visual indication of any hazardous areas or hidden obstacles. If you intend on crossing flowing water, check the speed of the flow - remember that a car will float and can get carried away downstream pretty easily so don't attempt this unless you are very experienced. If in doubt, abort the crossing and find another way round! Technique Whether you're entering a river, lake or a deep trough, you'll find most areas of water have a steep entry (A) and exit point (C) and submerged ground under the water which may or may not provide decent traction and support (B). Diagram 1: The anatomy of a deep water trough Entering the water When you descend the slope it's sensible to use exactly the same technique described on our hill descent article . Enter the water gently in a low gear to prevent a huge splash. Then accelerate slightly and change up if necessary when you're on a flat surface. Diagram 2: Entering the water On the flat Select a gear which provides a decent amount of traction, but reduces the chance of engine stall, and keep the engine in the power bend. Second gear in low range (if fitted) is usually about right, but if you don't have low range it's probably best to stick to first. By driving slowly and steadily (jogging pace) through the water you'll find that a bow wave naturally forms in front of the car. This is useful as it artificially lowers the level of the water at the front of the vehicle, crucially around the engine bay and air intake. Diagram 3: The bow wave Follow the wave and try to keep it about a metre in front of your vehicle for the best results. This provides an additional layer of protection for sensitive vehicle components, however if you stop this effect is cancelled out immediately. Ensure you can keep going once you've entered the water - the what you should check on the recce, or altenatively follow the path of a previsouly successful vehicle. Don’t let the engine stall - while the engine is running the gas pressure will prevent water entering the exhaust pipe (even if it's completely submerged). But if you turn the engine off or stall, the rapidly cooling gas will suck water up towards the engine and can clog up and damage the catalytic converter. If you do stall, try to restart the engine as quickly as possible and you should be ok, but if it won't start wait to be recovered to prevent costly engine repairs. Exiting the water When you're getting close to the other side it's a good idea to ease off the throttle - as the bow wave hits the bank it will come back towards the car and can splash well over the bonnet if speed isn't reduced. Climb out of the water using the techniques outlined in our article on climbing hills and you've made it! Reconnect the fan if necessary and continue on your adventure. ====================================================================== # Four wheel drive systems URL: https://www.drivingfast.net/four-wheel-drive-systems/ Category: Off-road The three main varieties of four-wheel drive systems are: Permanent / full time four wheel drive Manually selectable four wheel drive Automatically selected four wheel drive This article explains how each of these three systems work, and how to use them in the most effective way when driving off-road or in challenging conditions. Permanent / full time four wheel drive Permanent four wheel drive systems all follow the same principles, although the mechanical layouts can vary. Firstly, the drive (which exits the engine via a drive shaft) needs to be split in order to power the front and back axles simultaneously. This is done via a mechanical gadget called a differential. Full time four wheel drive systems have a centre differential (a), as well as a rear (b) and front diff (c) shown in Figure 1 below. The front and rear diffs split the drive to the wheels, and this is how all four wheels can be powered by a single engine. Figure 1: Permanent four wheel drive Introduction to differentials Differentials allow the drive to be split Differentials allow the drive to be split, but they also have another function, which is to allocate drive to each wheel in a flexible manner. When turning corners, each wheel takes a different path (see Figure 2). The inside wheels take a tighter arc than the outside, and in addition the front wheels take a slightly different path than the back. To allow this to happen, the same differentials which split the drive must also be able to distribute the drive at different speeds while maintaining forward propulsion - a tough job for one component. Figure 2: The different arc of the inside and outside front wheels Click here for an article on differentials The side effect of differentials This is all well and good, however this flexible approach to distributing drive has a side effect - it allows drive to 'escape' via the easiest route. Let's say we're driving a front wheel drive vehicle on a tarmac road, but one of the driven wheels is positioned on frictionless ice. When the driver tries to pull away they would find the wheel on ice spinning wildly, but the wheel on tarmac would not rotate forwards to propel the vehicle. This same principle applies to permanent 4WD cars - the flexible division of drive provided through the three separate differentials can prevent forward motion from occurring if just one wheel is on a slippery surface (a, Figure 3). Figure 3: Drive loss through one wheel (a) on a slippery surface This situation is far from ideal, especially as four wheel drive is meant to provide better performance in slippery conditions. But there is a solution - locking differentials and traction control. Most full time 4WD vehicles are fitted with a locking centre differential which, when engaged prevents the flexible division of drive between the front and the rear axles (b, Figure 4). So, as long as either the front or the back axles have decent grip, forward propulsion can be maintained. Suddenly that patch of ice isn't so much of a big deal. Figure 4: A locked centre differential (b) prevents drive loss between the front and rear axles, and maintains forward motion However, if you're really unlucky, one of the wheels on both the front and the rear axles could be on a slippery patch, and we're stuck yet again through the action of a spinning rear wheel (c, Figure 5). Figure 5: Even though the centre diff is locked (b) - drive is escaping through two wheels on slippery ground (a and c) To get over this problem, modern vehicles are usually fitted with electronic traction control system. Traction control systems prevent drive from escaping from a spinning wheel by applying the brakes to that wheel. If the brakes are on, the easiest route for the drive to travel is to the wheel on the high grip surface, thus forcing the car to continue moving. Alternatively, some hard-core off-road machines have front and rear locking differentials. With both these solutions we now have a robust four wheel drive powered car which can cope with a variety slippery conditions without getting stuck - phew! Manually and automatically selected four wheel drive systems The mechanics of a vehicle with selectable 4WD are quite similar to that of a permanent four wheel drive system, this includes a method of splitting the drive to the front and rear (a), and some differentials at each axle (b and c) to split the drive again for the wheels. Selectable four wheel drive Both manually and automatically selected for 4WD systems operate using the same principle - drive is permanent at one axle (usually the rear), and the other axle can be connected to the engine when required. The ethos of selectable four wheel drive is to engage four wheel drive only when conditions get tricky. This can be done manually via a switch or button, or automatically via some clever technology. The mechanism of connecting an additional axle to the engine can be done in a variety of different ways such as via clutch plates, viscous couplings, or other clever means. Depending on the vehicle you're driving, this can be done on the move or in some cases the car must be stationary - read your handbook to find out how your system operated. Note: Most selectable four wheel drive systems do not have a centre differential, which means they shouldn't be used in high traction conditions with 4WD engaged. Doing so may put unnecessary strain on the drive line when turning corners. ====================================================================== # Off-road driving techniques URL: https://www.drivingfast.net/off-road-driving-techniques/ Category: Off-road Welcome to the oevrview off off-road driving - this area introduces the skills and techniques required to make progress on tough off-road terrain in a four wheel drive ( 4WD ) vehicle. Off-roading at an advanced level requires mastery of your vehicle, a thorough understanding of the terrain and conditions, and an instinctive knowledge of what to do if things go wrong. It takes years of practice to drive well on varied terrain, and there is always more to learn. From snow and ice, to sand dunes, to rutted woodland tracks - driving in varied conditions is one of the most rewarding and adventurous hobbies in the world. Technology Learn about essential four wheel drive technologies which give you every chance of succeeding when the going gets rough. Discover how to distinguish between the various types of 4WD system, and the features of a capable vehicle. Four wheel drive systems 4WD vehicle features Techniques Master these techniques and you'll have a skill set which can be used in almost any situation. Controlling slides Pulling away Obstacles Understand the unique techniques required for specific off-road obstacles which are likely to be encountered. Climbing hills Deep water Descending hills Crossing ditches Terrains Terrain specific guidance is included below. Snow and ice ====================================================================== # Off-road snow & ice driving URL: https://www.drivingfast.net/off-road-snow-ice-driving/ Category: Off-road This article is aimed at 4x4 drivers to explain some useful techniques for driving in challenging winter conditions off the beaten track. Be sure you know what you're driving - many SUV models are now only two wheel drive, as these are cheaper, lighter and more fuel efficient. We counted the models of a popular SUV and found that only two models of 26 were actually four wheel drive. Even Land Rover now build two wheel drive variants of popular models, so make sure you do indeed have four driven wheels! Rules of thumb High / Low Range : Low for control, high for cruising Gears : Pull away in a higher gear than normal for extra traction Suspension : Raise if necessary to prevent grounding in deep snow Diff lock(s) : Engage when slippery Speed: Keep your speed down Traction control systems : Keep on unless a hindrance Weather forecasts : Use a good snow forecast app and be prepared Note : Leave more room for braking, ensure all driver inputs are gentle Preparation & equipment Driving in any adverse conditions requires some preparation. At the very least you should pack some warm clothes and a torch, but the following items may also provide invaluable: Specialist tyres and snow chains Recovery equipment such as correctly rated ropes or straps 'Sand' ladders or other traction aids Snow shovel Food and water Sleeping bag If you have a winch fitted, ensure you have a well maintained winch kit GPS Ice scraper and other common sense items Understanding the 4x4 system To make the most of your 4x4 you need to understand how the system works to know how to get the most from it and the various traction control systems which are available on modern vehicles. Read more about the four wheel drive system by clicking on the link below. Introduction to the four wheel drive system Techniques Driving technique is especially important when driving in tough winter conditions - the natural capability of a 4x4 can be dramatically extended when it is used correctly. Pulling away Ensure four wheel drive is engaged, and use low range gears (if fitted) when greater control is needed - this includes low speed manoeuvres or tricky undulating terrain. Pulling away in the highest practical gear will provide more natural traction due to the reduced torque being transmitted to the wheels. If you keep stalling when attempting to move off you've selected a gear which is too high. Ensure differential locks are engaged and electronic traction systems enabled to yield the best chances of pulling away successfully. There are occasions, especially when recovering a stuck vehicle, when disabling traction control systems can be beneficial, but it's usually best to attempt recovery with the systems enabled first, only switching them off if you've been unsuccessful. The traction systems which can occasionally be a hindrance are the variety which have the ability to reduce engine power as a result of traction loss - occasionally you'll need the ability to spin the wheels unhindered to provide maximum chances of recovery. Making progress Ok, so you've managed to pull away successfully and now you need to maintain progress. Deep snow can hide hidden obstacles such as rocks, branches and frozen pools of water. Drive at a sensible pace, but keep momentum up where possible - plan as far ahead as you can to plot a route and prepare for unexpected hazards. If you're driving on a well established track try to stick to the centre if possible to avoid drainage ditches. Driving in rutted snow If ruts have formed due to the action of previous vehicles, keep track of where your front wheels are pointing as steering feel can be dramatically reduced. It's very common for drivers to apply a certain amount of steering lock without noticing and the car will happily continue to follow the path of the ruts - this isn't necessarily a problem unless the wheels do eventually find traction as this could cause the vehicle to jump suddenly out of the ruts and off the track. A. Driving with steering lock applied. B. Vehicle continues straight. C. Front wheels find grip and jump out of the ruts Climbing hills If you absolutely need to climb hill to reach your destination, read our hill climbing tips below and remember to use the highest gear possible to give you the best chances of success. If you're struggling to make progress you can try 'steering for traction' which involves rapidly turning the steering about a quarter of a turn left and right repeatedly - you'll be surprised how effective this can be in really slippery conditions. Hill climbing technique Controlling slides Slides usually occur for two reasons - driver input or terrain. Keep all driver inputs as smooth and progressive as possible to make the most of available traction. Sliding on the flat If you do find yourself sliding while on the flat - you'll probably be experiencing either understeer or oversteer. Use the articles below to understand more about these two situations. Recovering from oversteer Recovering from understeer Sliding downhill If you're driving on a slope and start to slide downhill you'll need to react quickly to recover the situation. Avoid driving across a slope where possible - as a rule of thumb you should tackle these obstacles either straight up or down to gain maximum control. Use the article below to learn the technique for descending slippery hills. Remember that engine braking should be used to slow down the vehicle as a preference over braking, however in icy conditions even engine braking can cause a slide. Guide to driving down slippery hills Controlling slides Sliding while slowing down Always leave a serious amount of room to slow down, even if you have ABS fitted which will usually lengthen your stopping distance to maintain steering control - use this to your advantage to avoid hitting obstacles. Brake gently and progressively to reduce the chances of wheel lock, and remember that ABS is a reactive system so it's best to avoid activating it at all if you can avoid it (because it means you've already caused at least one wheel to lock). If you don't have ABS fitted, consider alternative braking techniques such as cadence braking. Learn more about ABS Braking techniques Recovery when stuck Even if you're the best driver in the world, there will be times when nature will get the better of you and your progress hindered. The techniques below may help if you do find yourself stuck in the snow. Whatever method you choose, remember to select the highest practical gear, use the absolute minimum throttle and wiggle the steering for best results. Clear snow from under the chassis If you're car is now sitting on a bed of compacted snow, it can be very difficult for the wheels to find grip - clear any snow away from the underside of the car and around the wheels with a shovel. Cutting channels for the wheels to follow can also aid progress. Reverse out the way you've come This may seem tediously obvious, but it's often much easier to reverse out using the tracks that your own vehicle has created than forging new ones by attempting to continue. This should usually be your first course of action. Rocking backwards and forwards If you're stuck in deep snow, sometimes a rhythmic rocking motion can be enough to free your vehicle - alternative between a suitable forwards gear and reverse, and attempt to start the car rocking forwards and backwards thus creating a small area of flattened snow which can be used to create sufficient run up to clear the obstacle. Use traction aids Sand ladders, snow chains, car mats and even cat litter can be helpful traction aids - use whatever you have at your disposal and put in front of the tyres in the desired direction of travel. Reduce tyre pressure Letting some air out of the tyres will increase the size of the contact patch and provide some valuable extra grip. Only use this as a last ditch attempt to get free, and if you need to get back onto the highway reduce your speed to the minimum practical speed and reinflate at the earliest opportunity. Towing If you're well and truly in the deep stuff, towing is usually a much quicker and easier option than winching. Use tow ropes or straps which are suitably rated for the weight of the stranded vehicle and attach to approved recovery points. Drive the recovery car until the rope is tight, then stop. Then pull away gently while the driver of the stranded vehicle gently spins the wheels of the stuck car. ====================================================================== # Off-road vehicle attributes URL: https://www.drivingfast.net/off-road-vehicle-attributes/ Category: Off-road Getting to know your vehicle is the first step towards being a safe and successful off-road driver. There are various natural attributes of your vehicle which determine the severity of the obstacles you can drive. These include the approach, departure and ramp angles, the ground clearance and the suspension travel. Approach, departure and ramp angles These angles (shown in Diagram 1 below) dictate the severity of slopes your vehicle can attempt without damage. The 'approach' angle (a) is the angle formed if you draw an imaginary line from the bumper to the bottom of the tyre, and dictates the degree of slope which can be approached without contact with the ground. The 'ramp' or 'ramp over' (b) angle determines the size of a ramp-like obstacle which can be tackled. The departure angle (c) is the angle at the rear of the car. Diagram 1: Approach (a), ramp (b) and departure (c) angles Angles Various vehicle accessories can affect the angles - a good example is a tow bar, which tends to protrude into the natural departure angle. If the departure angle becomes less than the approach angle you might find the rear of the car touches the ground when climbing particularly steep inclines. Diagram 2 highlights this issue using an exaggerated pick up truck to illustrate the problem. Diagram 2: A small departure angle means the back is likely to contact the ground Departure angle Ground clearance Decent ground clearance is vital if you want to make progress without dragging the body of your car over the ground. Ground clearance is usually determined by measuring to the lowest point on the car which is usually the differentials (if your 4x4 has solid axles). Diagram 3: Ground clearance (d) Ground clearance Suspension travel Good suspension travel allows all four wheels to remain in contact with the ground for as long as possible - this increases traction and will allow you to progress further before getting stuck. Diagram 4: Suspension travel determines the maximum articulation a vehicle can handle Articulation ====================================================================== # Pulling away off-road URL: https://www.drivingfast.net/pulling-away-off-road/ Category: Off-road When driving off-road, pulling away on the flat and on slopes without rolling backwards is an essential skill to master. This should become second nature if you're planning on becoming an accomplished off-road driver as it increases safety and makes success more likely. Rules of thumb Avoid the handbrake where practical Use the foot brake to secure the vehicle Avoid rolling backwards or coasting Pulling away in a manual transmission vehicle Hold the vehicle on the foot brake - this acts on all four wheels and usually has power assistance (unlike the handbrake which tends to operate on the rear wheels only without assistance). If you're trying to hold the car still on a slippery hill, you'll need all four wheels secured to reduce the risk of sliding. Select a suitable gear - higher gears increase traction but you're more likely to stall the engine. Release the clutch until the point of bite and hold it - you will notice the revs drop and the gear lever may move slightly. Gently release the brakes If the vehicle starts to roll backwards, reapply the brakes Release the clutch a few additional millimeters Release the brake gently - if done correctly the vehicle should be held stationery using the clutch alone If necessary, increase the throttle Release the clutch progressively and pull away Please note, this technique will increase wear on the clutch - but this should be expected when driving off-road to increase safety. Pulling away in an automatic transmission vehicle Hold the vehicle on the foot brake Select a suitable gear - higher gears increase traction but you're more likely to stall the engine. While holding the brake, increase the throttle slightly. Don't fight the brakes for too long as this can sometimes lead to overheating of the torque converter. Gently release the brakes If the vehicle starts to roll backwards, reapply the brakes Increase the throttle slightly Release the brake gently and pull away using sufficient throttle ====================================================================== # ABS system URL: https://www.drivingfast.net/abs/ Category: Technology Overview An ABS system consists of the following components: Some wheel speed sensors Brake calipers A hydraulic motor Some pressure release valves A quick thinking computer (or control module) which coordinates the whole process Diagram 1: Brake caliper (1) and wheel speed sensor (2) How ABS works When the driver hits the brakes this pressurises a hydraulic system which causes the brake pads to squeeze against the discs which causes the car to slow down. If the ABS system detects that one wheel is slowing down more rapidly than the rest (a symptom of wheel-lock) it automatically reduces the brake pressure on this wheel by opening a pressure release valve in the hydraulic system. ABS also has the ability to build the pressure back up via the hydraulic motor. The system reacts remarkably quickly, and compared wheel speeds many times a second. ABS systems can act on just the front wheels (which do most of the braking work), or all four depending on what car you're driving. Diagram 2: Wheel speed sensor (A), ABS control module (B), hydraulic motor and pressure release valves (C), Brake pipe leading to caliper (D) ABS in detail Diagram 2 (above) shows the whole process in more detail. The four wheels shown are braking heavily as a result of heavy brake pedal application, and the green wheel is about to lock up due a low friction surface such as ice. The ABS control module (B) detects the onset of a skid through the sensor (A) in this wheel and reacts by releasing the brake pressure slightly by rapidly opening a pressure release valve (C). This lowers the pressure in the brake pipe (D) which causes the brake caliper to loosen its grip on the brake disc on the locking wheel. If this corrects the locked wheel, the hydraulic motor (C) will build up the pressure again to the optimum braking force and the valve will revert to the closed position. If you've ever seen a car with ABS operating, you'll notice that the wheels appear to lock and release in jerky movements, this is because there is such a fine line between grip and traction loss in these conditions, and the system constantly tries to keep the pressure at the point just before lock up (which is the most effective pressure for slowing down). Three versus four channel systems There are two main types of modern ABS systems: three and four channel. Three channel systems control the braking pressure on both front wheels independently, but control the rear wheels together as a single unit. Four channel systems (as shown in Diagram 1) control the brake force on each wheel independently (assuming you're in a four wheeled vehicle!). In three channel systems, although both rear wheels are monitored by sensors, if wheel lock if detected on a single wheel the hydraulic braking pressure is reduced equally on both wheels. This does not provide the level of control of a four channel system, and thus three channel versions are compromised and usually only fitted to cars to save on cost. Most modern cars now use a four channel ABS systems which provide greater safety in emergency braking conditions. ABS software tuning The ABS ECU contains thousands of parameters which can be tuned for the car - although most ABS systems are supplied by companies such as Bosch, it's the software tuning which makes individual systems different for different cars. Vehicle manufacturers must strike a compromise between stability and the braking distance they hope to achieve, and must also set parameters for braking on different surfaces and scenarios. Even if two different cars have identical ABS hardware - it will have been tuned very differently for a sports car compared with an SUV. How can I make best use of ABS? ABS works best with a firm, steady application of pressure to the brake pedal. During ABS operation you're likely to experience some vibrations, which are the pressure release valves opening and closing and an indication that the system is working correctly. Don't release the pedal until you have safely stopped. braking with ABS versus no ABS You may have heard that it's possible to slow down quicker in a car without ABS. This has elements of truth, but in practical terms the benefits of ABS massively outweigh the slightly longer braking distances. For road use, ABS is an absolute must as it will allow you to steer out of the way of unexpected hazards. Diagrams 2 and 3 below explain the practical reasons for ABS. With ABS enabled In the diagram above, the driver hits the brakes hard on a slippery surface (1), then steers (2), and successfully manages to avoid the obstacle. ABS prevents the wheels from locking, and this allows you steer. Without ABS enabled Without ABS, as the driver applies the brakes the wheels lock (1). Despite applying steering lock, the car continues straight ahead due to the loss of steering control (2) and a collision results. ABS braking on the track If done correctly, threshold braking can slow a vehicle more quickly that a car fitted with ABS (in the right conditions). Many competitive racing drivers would say that they prefer their cars not to have the system. However, to gain maximum advantage you will need to practice the threshold braking technique repeatedly. A good test is to find a section of test-track, and mark out a cone which will act as the braking point. Accelerate to 60 or 70mph and brake as hard as you can in a car equipped with ABS, then repeat without ABS. Compare the stopping distances by having someone mark them on the side of the track, then practice threshold braking until you notice a marked improvement. If you do have ABS fitted, don't get into the habit of locking up wheels before entering a corner - this isn't the quickest way of slowing down and can unsettle the car. Article on threshold braking technique ====================================================================== # Biofuel URL: https://www.drivingfast.net/biofuel/ Category: Technology At first glance, biofuel might seem to be the a decent solution to several of the developed world's problems. Dwindling fossil fuel reserves, the high price of petrol and diesel, the constant pressure to reduce carbon dioxide emissions and the struggle to make a profit from farmland are all pressures which have resulted in a growing market for biofuel. Introduction Marketed as a cheaper, cleaner alternative to most traditional fuels, biofuel can be made using several sources including the following: Maize Rapeseed Corn Sugarcane The trade-off a In theory, the carbon dioxide produced by the burning of biofuels is partially offset by the gas absorbed by the plants during growth, and in some cases the fuel itself produces less carbon dioxide per gram burned. This all seems like positive news, however the most commonly used biodiesels are derived from maize and rapeseed, which pollute 50% and 70% more greenhouse gas than fossil fuel. In addition, significant energy is needed to grow the crop, further reducing the benefits. Consequences There are additional, more immediate and serious consequences of biofuel which driven by the economic benefits. On a global scale, farming is not very profitable (especially in less developed countries). The sudden demand for biodiesel has created an opportunity which is hard for traditional farmers to ignore. In addition, the demand is now so great that huge areas of rain forest are being cleared to make way for more farmland. Summary Do not believe the marketing campaigns - biofuels are doing lasting and serious damage to our already threatened planet. Please research this topic for yourself using credible independent sources. Help stop one of the greatest misunderstandings of this decade. If you want to help reduce carbon emission, cycle more or buy a low emission diesel such as the two cylinder Fiat 500 (which is also great fun to drive). ====================================================================== # Differentials explained URL: https://www.drivingfast.net/differentials-explained/ Category: Technology Spinning wheels are most likely to result from cornering while on the gas, pulling away from a stand still or accelerating in a car with lots of power Now a little more depth... Differentials - an introduction Before understanding why a limited slip or locking differentials are important, first we'll briefly need to touch on why we need a differential in the first place. In simple terms, a differential is a device which allows for the differences in wheel speed which naturally occurs when a car turns a corner. As you can see in Diagram 1, the inside and outside wheels of a car turn in different radius corners, and thus need to rotate at different speeds (with the outside wheels travelling faster). However at least two of the wheels will also need to be linked to allow the car to be two wheel drive. Consider a front wheel drive car with the two front wheels linked together with no flexibility, such as with a solid axle between them. Diagram 1: Cornering with a front differential In this case a certain amount of tension would build up when cornering as the outside wheel tries to rotate quicker that the inside wheel (due to the bigger arc it must go through). Eventually this tension would relive itself with a wheel skipping over the surface, or with a drive shaft snapping. This situation is obviously not a good one, so differentials where invented (see Diagram 2). Diagram 2: A basic differential positioned between two driven wheels As you can see, a diff is essentially a combination of cogs which work together to turn the wheels. It looks complicated, but it uses simple mechanics to allow the two wheels to rotate at different rates. Diagram 3: A close up of a differential How a differential works: The drive from the engine rotates the large yellow crown wheel (1), which is attached to the smaller blue cogs (2). These planetary gears can rotate freely, but work together to turn the green side gears, which are connected to the half shafts (3). If one wheel needs to rotate faster than the other, the green cogs permit this to happen. Simple really! Limited slip differentials Differentials work by allowing a flexible distribution of drive between the wheels on an axle, which allows for the different rates of rotation while cornering. However this flexibility is also the differential's weakness, as it will always allow drive to 'escape' via the easiest route. So if you are turning a corner while hard on the gas in a powerful car, you can find that the inside wheel starts spinning (due to the weight transfer leading to less grip), and you lose the ability to put power down on the road via the outside wheel. This isn't good, especially if you're trying to put in a good time on the track, and this is why the limited slip differential ( LSD ) was invented. The differentials shown in the diagrams above are known as 'open' diffs which means they have no mechanism to prevent this drive loss. The first LSDs connected the two half shafts together with a clutch pack allowing a limited amount of clutch slip between each side of the axle. This allowed for the relatively small differences in rotation while cornering, but prevented violent wheel-spin from just one of the wheels which could lead to loss of drive. Types of limited slip differential Today there are a variety of differentials which can reduce unwanted wheel-spin on one side of an axle, which is prevented using either viscous, mechanical, hydraulic and electronic systems. A simplified example of a clutch type LSD is illustrated in Diagram 4 below. Many race bred cars have LSDs fitted as standard, especially powerful front wheel drive cars which are more prone to wheel-spin while pulling out of a corner. Diagram 4: A clutch type LSD (limited slip diff) In Diagram 4 above, the simple open differential has been fitted with a clutch (1). This clutch prevents the two blue side gears from freely rotating independently which can help in the occasions when drive loss would be an issue, however there is enough flexibility in the system to allow small differences such as when cornering. Clutch packs such as these as usually held together by a spring, which automatically keeps the clutch tight even when it has worn down. The strength of the spring determines how aggressive the LSD becomes. Article on differentials and the four wheel drive system ====================================================================== # EBD explained URL: https://www.drivingfast.net/electronic-brake-force-distribution-ebd-explained/ Category: Technology When braking heavily in a car you get a dramatic forwards weight transfer. The body pivots forward, the front suspension is compressed, and more weight is transferred to the front tyres. More weight acting on the front tyres means more grip is available, and conversely the more lightly laden rear wheels have less grip at their disposal. If an equal amount of braking force was applied to the front and rear wheels in a heavy braking scenario, the lighter rear wheels would run out of grip first and be much more prone to wheel lock (see Figure 1). Figure 1: A car with an equal front to rear braking bias braking heavily, resulting in rear wheel lock Braking rear lock Most cars however, have a brake bias which sends the majority of the braking effort to the front wheels to counter this effect, however in this case the ratio of front versus back is fixed. Electronic Brake Force Distribution (EBD) provides an automatically adjusting bias depending on conditions to ensure the front and rear axles exert the most effective braking possible without wheel lock. EBD systems work in conjunction with ABS and use an electronically controlled valve which diverts hydraulic pressure to the front and rear axles in real time according to the conditions and scenario. Dedicated article on braking techniques ====================================================================== # Electric cars URL: https://www.drivingfast.net/electric-cars/ Category: Technology The internal combustion engine has been around for hundreds of years, and although the original pioneers of this technology would hardly recognise a modern engine, the fundamental principles have remained the same. Improvements in efficiency, power output and refinement have been made at an astonishing rate, but propulsion systems have now entered a rapid and crucial stage of evolution. Fossil fuel powered cars are becoming increasingly unfashionable and the motoring industry has responded to customer concerns about the environment. The beautiful Lightning GT: an electric supercar Lightning GT Introduction Billions of dollars are being invested throughout the world in the technologies which will power the next generation of consumer vehicles - and this is a very exciting prospect. Countless start-up technology companies are competing for their innovations to be adopted by the big players, resulting in a wide diversity of potential options for the car of tomorrow. Here we examine whether electricity could be the fuel of choice for the next generation of sportscars. So what are the main pros and cons? There are a lot of reasons to like electric motors - the technology is proven and relatively advanced, they have massive torque and are much more efficient in turning stored energy into motion. The French land speed record breaking TGV train used motors on each carriage for propulsion and it wasn't exactly sluggish. However, the train did have one distinct advantage over an electric car - a limitless supply of electricity supplied through the overhead cables. Batteries are the weak link at the moment, they're heavy, slow to charge on domestic power, and only provide limited range. Tesla currently use a huge bank of laptop batteries as their power source which isn't exactly cutting edge, but the technology is gradually catching up. When it does, here's a summary of what we have to look forward to… Motor layouts Single motor The single motor design has been the first to be adopted due to the similarity with existing cars - a large individual motor can sit where the engine used to be, and powers two or four wheels via some differentials and drive shafts. This layout works well, and minimises the need for complex control electronics, however there is another way… Multiple motors Several smaller, lighter motors can be used to power each wheel individually (as used in the beautiful Lightning GT). These motors can be mounted inboard or even inside the wheels. This removes the need for any differentials and other transmission components and allows much greater control of each individual wheel. Cars using this layout can have much greater flexibility in terms of design and aerodynamics, and will benefit from more accurate traction control systems (discussed below). Performance overview Acceleration Acceleration where electric motors excel. They have huge amounts of torque all available from a standstill, and have no need for a clutch or gearbox, so no valuable seconds will be lost fumbling for second gear. Great news for your quarter mile times! Top speed Top speed isn't so great - as you go faster, you consume energy at an exponential rate and this drains batteries quickly. Most electric cars will have artificially limited top speeds to maintain decent driving range. Don't expect any Veyron beating high speed runs. Weight Batteries are currently pretty heavy, but can be distributed in a flexible manner which means the mass can be kept close to the ground (creating a low centre of gravity), and spread equally between the front and rear (for more balanced handling). Electric cars do not require heavy conventional gearboxes due to the increased rev range of the power plant, and in-wheel motors remove the need for almost all driveline components, saving weight significantly. Driveline and traction systems This is where things start to get interesting - although many electric cars will use a single large electric motor as an engine substitute, some manufacturers are experimenting with several smaller motors which power each wheel individually. Suddenly traditional traction systems such as limited slip differentials, launch control, and brake-based traction control are out of the window. Torque can be divided much more accurately between each wheel depending on the conditions and driver inputs, leading to the best possible grip and performance. Noise Not exactly exciting to listen to. Artificial 'sound generators' exist but these may put off the purists. A genuine, decent sounding motor needs consideration. Maintenance With only a few moving parts, electric motors have greatly reduced maintenance requirements. There is much less wear and tear, no reliance on an oil reservoir and very little that can go wrong. Regenerative braking Finally onto regenerative braking, which is already used in some hybrids, regenerative braking allows some of the energy lost during braking to be captured by using the motor in reverse as a generator - simply reversing the polarity allows the motor to generate braking force and help recharge the batteries. Related links Hybrid car technology Why biofuel is not environmentally beneficial Driving for economy ====================================================================== # Gearbox technologies explained URL: https://www.drivingfast.net/gearbox-technologies-explained/ Category: Technology Gearboxes are complex mechanical devices which allow cars to operate at different road speeds while remaining within the rev range of the engine Many performance cars are now fitted with 'paddle shift' style switches behind the steering wheel which are often marketed as sequential gearboxes, however these are often not true sequential mechanisms, but simple electronic manual controls to fairly standard automatic transmissions. Below is an introduction to some of the different transmissions which can be fitted in performance cars: Automatic transmissions with manual control (e.g. Tiptronic) Technical summary Standard automatic transmission with manual controls Torque converter rather than clutch These 'Tiptronic' style systems allow the driver to have greater control of gear selection in a car with automatic transmission by offering a 'manual mode'. This mode can be controlled using paddle switches behind the steering wheel or by selecting a dedicated slot on the transmission control. The more advanced versions of this system are linked to the engine management controls, automatically raising the engine speed in response to a downshift and achieving the same quick, smooth gear change as heel and toe shifting allows. Even when in manual mode, certain failsafe controls are built into the system which will prevent. for example, the engine stalling from the revs dropping below a set limit. Good Tiptronic systems can reduce the shift time compared to a manual transmission, but many will not. Advantages Paddles allow the driver to keep both hands on the wheel while changing gear Can allow the driver to lock the system into a particular gear, allowing the engine speed to run all the way to the rev limiter and extract full power from the engine Permits down changes in anticipation of a corner which will prevent unnecessary changes mid bend, which could potentially unsettle the car Disadvantages Not as quick as DSG or true sequential gear changes Possible slight loss of power through the torque converter What to look for: Paddles which rotate as you turn the steering allow easy changes when steering lock has been applied Example trademarks for this system: Tiptronic (Porcshe) Steptronic (BMW) TouchShift (Mercedes) SportShift (Subaru) Direct Shift Gearboxes (DSG) Technical summary Manual gearbox with automatic or semi-automatic control Dual clutch, twin shaft Predictive pre-selection of gears DSG gearboxes are a recent addition to the suite of technology now becoming readily available in production cars. The idea behind DSG is to provide fast gear changes with the longevity of a conventional automatic gearbox. DSG is essentially a computer controlled manual gearbox complete with two clutches which each engage a different selection of gears. The first clutch engages the gears 1, 3, and 5 with the even gears engaged by clutch two. The beauty of the system is that the computer can predict which gear you're likely to select and pre-select this (as long as it's either one up or one down). When shifting to the pre-selected gear, all the system needs to do is release one clutch and engage the other. This can be done incredibly quickly and results in lightning changes. The computer takes into account a variety of driver inputs when deciding which gear to select including throttle position, engine speed and road speeds. Drawbacks of the system include the relatively heavy weight when compared to conventional manual or sequential gearboxes, and the fact that the really fast changes will only occur when the computer has pre-selected the correct gear. Advantages Can provide extremely rapid gear changes to expected gears Disadvantages Can be heavy due to added cogs and shafts required Relies on a computer to predict the gear that is likely to be chosen, unexpected changes can increase change time Expensive True sequential gear boxes Technical summary True manual gearbox Ability to shift without the use of a clutch Fastest consistent shift speeds You'll usually only find true sequential gearboxes in fairly serious racing cars as they're expensive and require regular maintenance. However if you're trying to shave precious seconds off lap times there's no substitute. There are two main advantages of a sequential box which include the ability to rapidly change gear without a clutch, and the reduction in error which can result from a standard "H" gate gearbox. How to use a sequential gearbox True sequential gearboxes are usually set up to change down by pushing the lever forwards, and to change up by pulling back. The reason for this is that when braking hard, the resulting weight transfer will throw your body forwards and as this is when you're most likely to change down, pushing the lever will be easiest. When accelerating hard your body will be thrown backwards, and pulling the lever will be the most natural motion It's important to push and pull the lever in a very deliberate rapid motion to ensure correct engagement of the desired gear. Advantages Extremely quick changes regardless of which gear is selected Impossible to block change into the wrong gear Disadvantages Expensive to buy and repair Due the high levels of wear and stress involved with a mechanical sequential gearbox, you may find you need to rebuild it every now and then to ensure continued efficiency, this pretty much rules it out of most road cars. ====================================================================== # Hybrid car technology URL: https://www.drivingfast.net/hybrid-car-technology/ Category: Technology Hybrid vehicles attempt to strike a balance between the more versatile combustion engine and the more economical electric motor. A number of different options exist, and this article attempts to simplify the technology and highlight the differences between modern hybrid systems. Hybrid technology comparison Hybrid type Integrated electric motor Engine / motor axle split Extended range electric vehicle Also known as Parallel hybrid Parallel hybrid Series hybrid EREV Advantages Most conventional car-like option Compact Allows larger engine / motor variants to be used Allows usage in high performance cars All the efficiency benefits of electric propulsion without a compromised range Quiet at all speeds and engine loads Disadvantages More expensive than an efficient petrol or diesel option Reduced usable space Complex synchronisation is required between motor and engine Reduced usable space Reduced top speed versus combustion powered equivalents Variants Plug-in / stand-alone Petrol / Diesel Start-stop Single motor Dual motors In-wheel motors Plug-in / stand-alone Petrol / Diesel Start-stop Single motor Dual / quad motors In-wheel motors Plug-in / stand-alone Petrol / Diesel Start-stop Examples Toyota Prius Honda Insight Porsche GT3 Hybrid Honda NSX Infiniti Emerge Peugeot 3008 Chevy Volt Vauxhall Ampera Electrically assisted hybrid cars [Sometimes known as parallel hybrid cars] If a car contains both a combustion engine and electric motor, it is unlikely that the electric power will be used as their dominant source of propulsion for high speed cruising. To gain maximum efficiency benefits, the challenge for designers is to ensure that the electric motor can contribute when the greatest benefits can be realised. Fully integrated Fully integrated hybrids combine conventional engine and electric motor outputs into a single source. The electric element of the powertrain assists the engine when required but is not essential for progress to be made. The motor usually kicks in when pulling away or when an extra burst of acceleration is required. A 'start-stop' feature is usually employed on the main engine, and this allows maximum efficiency when driving in city conditions. Early hybrids were exclusively petrol due to the relatively quick and easy engine start associated with this fuel, but diesel hybrids are likely to become more common in future as this issue is tackled. Power is provided by a bank of batteries, which is recharged by making use of excess powertrain energy (such as when slowing down, coasting or braking). Diagram 1 : Integrated hybrid (front wheel drive) A . Petrol or diesel engine B . Integrated electric motor C . Differential D . Battery bank Integrated hybrid technology is often used for the more affordable end of the market due to the relative simplicity and user friendliness of these systems. Pioneers of the technology include Toyota and Honda. Examples of integrated hybrid cars: Honda Hybrids [e.g. Insight, CR-Z] Honda Integrated Motor Assist Honda Insight Toyota Hybrids [e.g. Prius, Auris] Toyota Hybrid Synergy Drive Toyota Prius Engine / motor split by axle The second natural method of creating a hybrid powertrain is to split the electric motor and the engine by axle. Hybrids with a dedicated electric axle have a number of potential layouts: A single motor and differential to split the drive to both wheels Dual inboard motors, with computer controlled variable speed control (shown in diagram 2 below) Dual in-wheel motors Advantages of the split layout include the ability to power all four wheels simultaneously, to reduce packaging complexity, and to use a larger engine / motor combination. Most hybrid supercars use this layout, usually with the engine driven wheels at the rear. Diagram 2 : Electric motor powered front axle, combustion engine powered rear wheels A . Petrol or diesel engine B . Differential, C . Electric motor (or dual motors in this case) D . Battery bank The dual motor technology shown as an example in Diagram 2 is more complex and expensive to produce, and is only likely to be realised in higher performance hybrids or electric vehicles. Some examples of the application of dual high performance electric motors are shown below. high performance hybrid supercars A new generation of hybrid supercars are now emerging - a strategy primarily driven by tough new emissions legislation applied both to road cars and in racing. To satisfy the traditional sports car owner, most high-performance hybrids will maintain conventional power at the rear axle to deliver a sporty feel and top speed performance, so the natural use of the electric motor will be to contribute at the front. As the technology has advanced, the idea of hybrid sports cars has become more appealing due to the fact that electric motors have the benefit full torque available immediately. When applied correctly, this can help fill the flat spots in a conventional engine's power curve and improve relative performance. The challenge for manufacturers is to overcome the weight disadvantages associated with the high output battery packs required for these products. Expect to see hybrid systems appearing in many more high-performance cars as the technology improves. High performance hybrid / electric examples: Mercedes SLS AMG E-Cell Mercedes E-Cell SLS dual motor electric drivetrain Mercedes E-Cell SLS exterior Mercedes SLS E-Cell powertrain Porsche 911 GT3 Hybrid Porsche 911 GT3 electric motors Porsche GT3 Hybrid exterior Porsche GT3 Hybrid powertrain Honda / Acura NSX Infiniti Emerge The Honda NSX has a split axle hybrid powertrain The Infiniti Emerge uses split axle hybrid technology Extended range electric vehicle [Sometimes know as 'series' or range extended hybrid cars] Engine assisted hybrids vehicles use an electric motor as the sole source of drive, so these are essentially electric vehicles. However they address the range constraints of a typical electric car by using a more conventional combustion engine when required to recharge the batteries and extend the life of the batteries. The engine is never used to directly power the wheels, and this means it can operate in the most efficient conditions to maximise economy. Diagram 3 : Range extended electric vehicle A . Electric motor as the primary source of propulsion B . Differential C . Engine / generator D . Battery bank Range extender hybrid examples : Chevrolet's range extender hybrid Volvo range extender hybrid Regenerative braking Regenerative braking is an energy recycling method used on most hybrid and electric cars. The idea is to convert the kinetic energy (which is usually lost as heat during braking) into usable electricity to recharge the battery pack. Energy is usually captured by using the main electric motor in reverse (as a generator), which is connected to the wheels automatically when braking is started. The Porsche GT3 hybrid uses a high speed flywheel to store captured braking energy, when is then released on demand to power the motors. hybrid Glossary EREV - Extended Range Electric Vehicle Full hybrid - the ability to run on either the engine, the electric motor, or a combination of the two Mild hybrid - a car which cannot be powered by the electric motor alone Parallel hybrid - both the engine an motor are connected to the transmission which powers the wheels PHEV - Plug-in hybrid electric vehicle (can be charged by plugging-in) Series hybrid - only the electric motor can drive the wheels, the engine simply charges the batteries ====================================================================== # Stability control systems explained URL: https://www.drivingfast.net/stability-control-systems-explained/ Category: Technology Electronic stability control systems (SC for the purposes of this article) detect loss in traction and react to regain grip using the braking and engine management systems. Situations where the systems will come into action include understeer, oversteer, and spinning wheels. Most new vehicles are now fitted with some kind of stability control system. There are a host of acronyms for this technology which varies according to car manufacturer… Electronic Traction control (ETC/ TCS) Dynamic Stability Control (DSC) Electronic Stability Programme (ESP) Porsche Stability Management (PSM) Etc Don't be fooled into thinking each of these systems are unique - they all function in very similar ways (and are usually all made by the same manufacturer). How do stability control systems work? Sensors In order for the car to detect loss of traction it needs some sensors. These come in various different forms and determine how the car is behaving, and what the driver is trying to do. Yaw sensors, gyros, wheel-speed detectors and accelerometers are the most common sensors found in SC systems. In addition, information ranging from steering and pedal position, engine speed and gear selection is used to determine driver inputs. How is this information used? When the SC system determines that loss of traction is occurring, it acts using the braking and engine management controls (and in some cars even the steering system) to put the car back on track. The system reacts according to a set of preset criteria depending on the nature of the loss of traction, which can include spinning wheels or slides. Spinning wheels Traction control is used to reduce drive loss through spinning wheels. This can occur when driving on slippery surfaces, or when accelerating hard (usually in first gear from a stand still). Traction control reacts by applying the brakes to the spinning wheel and this forces the drive to be diverted to the wheel(s) with the best grip. Traction control usually only operates below a certain speed. Sliding There are two different types of slide - understeer and oversteer. SC systems react to these situations by applying the brakes to individual wheels, and reduce engine torque when appropriate to keep the car on line. During an understeer situation, torque is reduced and the resulting forwards weight transfer is usually enough to regain control, if this is not sufficient to bring the vehicle back in line, individual rear brakes will be applied. When oversteer is occurring, brake force is applied to one of the front wheels, which acts as pivot to bring the car back on line. In general, the brakes are only applied to the wheels which are likely to have the most grip. how does the system apply the brakes? Almost every vehicle now has ABS fitted as standard. This life-saving system allows you to continue to steer while braking by regulating the brake pressure and preventing wheel-lock. The system uses a hydraulic motor to generate brake pressure, and this same motor is used by the SC systems to apply braking force to individual wheels where possible, and valves in the ABS unit regulate the pressure. Disadvantages of Stability Control systems As discussed above, SC systems use both the brakes and engine management controls to reduce wheelspin or slides. Great on the road, but when you're on a track the last thing you need is the car putting on the brakes! Most performance cars have an option to disable (or significantly reduce) the SC systems via a button on the dash. Experiment by turning off the control and see how the car behaves. If you have got into the bad habit of allowing the SC systems to sort you out round corners, you may find yourself spinning in the first bend, so be careful and build up speed gradually as your confidence improves. ====================================================================== # Best motorcycle sat navs URL: https://www.drivingfast.net/best-motorcycle-sat-navs/ Category: Motorcycles Your options If you want to use a sat nav device on your bike you have three main options - Adapt a car sat nav Buy a specialist motorcycle device Use a smart phone Main considerations In this article we look at the following features, concentrating on the core functions of the devices - we're not going to worry too much about low priority extras such as media playing capability. Quality of the device including routing and responsiveness Ability to survive a downpour Viewing in direct sunlight Mounting quality and stability Use with gloves Good battery life, as you may not be able to charge it on the go Directions via headphones or bluetooth device Speed camera warnings, not that you'd break the speed limit. Honest. Summary of the best sat navs on the market Device Review Rating Price Garmin Zumo 590LM Garmin's flagship motorcycle device with all the trimmings including optional tyre pressure monitoring, very impressive, but very expensive. 5/5 Expensive TomTom Rider TomTom's dedicated motorcycle sat nav, similar features to the Garmin in a more compact package. 4/5 Quite expensive Google maps and a smart phone Google's well developed app. Pop it in your pocket and get spoken directions via headphones. Not glove friendly, and smart phone dependent. 4/5 Free Garmin Zumo 590LM Garmin Zumo Click here to view the Garmin Zumo 590LM on Amazon Garmin's flagship motorcycle sat nav is well developed, rugged, innovative and desirable. However, be prepared to splash a significant amount of cash for the privilege though, over £500 at the last count. This is the current class leader - it has a number of premium features, and the build quality is excellent. Vertical and horizontal mounting is supported, so you can choose between seeing more of the route ahead or more peripheral information. It has been designed to be easy to use with gloves, in the rain and can withstand vibration and even fuel spills. An off-road mode with 3D terrain will suit the more adventurous rider, and the road directions and clear and can be beamed to a comparable bluetooth device. It provides useful lane assist information and intuitive guidance, so you're not left scratching your head at complicated junctions and has various predictive and scenic route planning features. The LM suffix signifies lifetime maps which are updated frequently - this service was pioneered by Garmin, but now TomTom also offer this service on comparable devices. Garmin were playing catchup with TomTom for many years on user interface and usability, but the latest generation of their navigation software is very good, responsive and accurate. It's not all good through, Garmin's Basecamp software is notoriously annoying to use, and requires connection to the device to access maps and routing capability. Key strengths Well constructed, premium hardware Latest generation, feature rich software on a par with TomTom's best Easy to use, easy to see Tyre pressure monitoring with optional valve cap gadgets Some hands-free features via bluetooth Intuitive guidance Main Weaknesses Traffic information needs smart phone connection and app Basecamp software is frustrating and under-developed Large unit can obscure instruments Features Screen size 5 inch Glove friendly Yes Sunlight readable Yes Hands free control Yes Waterproof Yes Rugged Yes Traffic Via smart phone app Lifetime map upgrades Yes Battery life 4 hours Handlebar mount Yes Speed cameras Yes Unique features Tyre pressure monitoring TomTom Rider V5 TomTom Rider Click here to view the TomTom Rider on Amazon TomTom now only have one dedicated motorcycle sat nav unit - the Rider. There have been several iterations, and we're talking about the V5 2014 model. As you would expect from a TomTom, the software is proven, nice looking and well developed. The car user interface has been adapted for use with gloves, but in our view they haven't gone far enough. The search results pages have too many lines to accurately poke with our stubby fingers and certain other buttons are tricky to press with consistent accuracy. The unique feature of the TomTom is the 'Tyre' software which allows for route planning and community sharing - it's far better than Garmin's Basecamp software, however it's not perfect and you will encounter frustrating difficulties when planning routes for real such as when tailoring a community route with your own way points. Route calculation can take some time, and the unit feels slightly underpowered for the sophistication of the software. Personally, I'm very frustrated by the hardware in most of TomTom's offerings - they just don't have sufficient processing power to recalculate routes in an decent time. This feels like a cost saving measure which just shouldn't be acceptable in the age of inexpensive hardware components. Visibility is good due to the mini sun visor, the quality of the screen, the strength of the backlight, and the interface colour choice. The high quality Ram Mount does a great job of keeping the unit steady and absorbing vibration. With the optional accessories pack, you get a lot of additional mounting options including a wiring kit to connect to your bike's battery. Key strengths Class leading unit software and interface Good PC based route planning software Decent sunlight visibility Leading route quality Usual TomTom route quality Numerous mounting options Good battery life Main weaknesses Not perfect with gloves Surprising lack of features such as traffic Route recalculation can be slow if you miss a turn No external speaker, not that you could hear it at cruising speeds. Some users report the voice commands getting 'out-of-sync' Features Screen size 4.3 inch Glove friendly Yes Sunlight readable Yes Hands free control No Waterproof Yes Rugged Yes Traffic No Lifetime map upgrades Yes Battery life 6 hours Handlebar mount Yes Speed cameras Yes Google maps smart phone app Google Maps Google Maps is available as a free app for both Android and iOS smart phones. The Android version is usually slightly more advanced than the Apple equivalent, although updates are made regularly. If you decide to go for this option we recommend using headphones, setting the route, popping the phone in your pocket and listening to the guidance. If you decide to mount the device you'll need to buy the relevant accessories - Ram Mount do have options for most popular phones, and waterproof cases are readily available. Key strengths Intuitive Excellent routing Comprehensive and accurate points of interest Accurate real-time traffic Free Main weaknesses Not easy with gloves Can drain battery rapidly unless you turn the screen off Features Screen size Smart phone dependent Glove friendly No Sunlight readable Smart phone dependent Hands free control No Waterproof Unlikely Rugged Unlikely Traffic Yes Lifetime map upgrades Always up-to-date Battery life Smart phone dependent Handlebar mount Available for most devices Speed cameras No ====================================================================== # Getting the best motorcycle insurance deal URL: https://www.drivingfast.net/getting-the-best-motorcycle-insurance-deal/ Category: Motorcycles So, you've passed your CBT and have been riding a 125 for a while, but you're bored of all that and now it's time to upgrade to your first proper bike. We're in the same boat, and here are a couple of options we considered for this insurance experiment. All naked bikes, all good commuters, and they all look pretty good (a major consideration for us!): Honda CB600F Hornet Yamaha XJ6 Honda CB500F KTM Duke 390 KTM Duke 690 Remember that insurance companies play with statistics, so sometimes strange choices can make a massive difference to the amount you'll pay for your premium. An example is your choise of bike - a KTM Duke 390 (a mad looking bike) has a much higher premium than a very sensible Honda CB500F (with almost identical power). This is almost certainly due to the fact that Honda owners are a more sensible bunch and statistically a safer bet. Your choice of bike Make, insurance category Very important - some bikes are more desirable to thieves, and some are more desirable to braver riders Value Moderately important, but adding ?1000 to the value doesn't tend to increase the premium as dramatically as the choice of bike Your experience Years licence held Very important - experience is a great way of reducing your tendency to get into an accident No claims discount Very important - indicates your risk to the insurer Where your bike is kept Post code Very important - crime hotspots are very localised, sometimes a small change to postcode makes a good difference to your premium Locked compound Minor - this is roughly the same as keeping on a public road Public road Minor Garage Very important - in the eyes of the insurance companies, this is the most important storage based decision you can make Private property Minor Security devices Immobiliser, alarm Important Locks, chains, disc locks etc Minor importance to insurance premium, but useful to prevent a claim Conclusion To get the best insurance premium: Pick a sensible bike at first and don't modify it from factory specification (unless adding security features) Choose a bike with an immobiliser Concentrate in getting few years experience and no claims discount under your belt Store the bike in a garage To prevent your bike being stolen: Keep it somewhere sensible and hard to access Use an expensive chain, attach it to something solid, and put it through the chassis (not the wheels). The easiest method of nicking a bike is to lift it into a van. Fit an alarm ====================================================================== # Guide to junctions for new motorcycle riders URL: https://www.drivingfast.net/guide-to-junctions-for-new-motorcycle-riders/ Category: Motorcycles Types of junction The UK driving standards agency (DSA) defines junctions as one of the following: T-junction Y-junction Crossroads Roundabouts Staggered junctions This article will cover all of the above. Junction options While riding on a major road* you may want to... Continue straight on passing a minor road Leave by turning right onto a minor road Leave by turning left onto a minor road While riding on a minor road, you may want to... Cross a major or minor road travelling straight ahead Emerge into major road by turning right Emerge into a major road by turning left *Note: A major road is defined as one with priority over another road at a junction. Things to do at any junction The UK driving standards agency uses the OSM PSL acronyms, which are used in all their materials and these stand for the following: Observation Understand the general traffic situation Anticipate hazards Check mirrors Signal Use the indicators in good time to let other road users know what you're up to Manoeuvre Use the PSL routine Don't forget to cancel your indicator once you've completed the turn Position When turning left, head to the left of the road, or go to the centre of the road (on a two way street) if you plan to turn right. Speed & gear You'll normally need to slow down to take a junction, so roll of the throttle gently, apply the brake if necessary, and select a gear which will take you through the corner without a further change. Look Look around the corner as soon as you have visibility. Watch for traffic and hazards. Turning left from a major to a minor road Turning left from a major to a minor road Main potential hazards A . Cyclists, other motorcycles on your left undertaking or in your blindspot B . Parked cars may affect your ability to position toward the left hand side of the road C . Cars could brake suddenly and turn without indicating Procedure for major to minor road, turning left As with all manoeuvres, perform the OSM PSL procedure. Check your mirrors first, and indicate to show your intentions. Before you change your position, it's sensible to do a 'lifesaver' over the shoulder check to watch for cyclists or other motorcycles which may be undertaking. As you move towards the left you'll probably need to reduce your speed and select a gear which will take you through the corner. As left hand turns are usually sharper than right handers you may need a lower gear. Look through the corner as soon as you can see, decide to take the bend, then start to move towards the centre of the road and cancel your indicator. Turning left from a minor to a major road Turning left from a minor to a major road Main potential hazards - Fast moving traffic approaching from the right on the major road - Restricted vision approaching the junction A . Cyclists, other motorcycles on your left undertaking or in your blindspot B . Parked cars may affect your ability to position toward the left hand side of the road C . Cars turning right off the major road cutting the corner Procedure for minor to major road, turning left Follow the approach procedures of a left turn from a major to minor road , however when turning onto a major road, the chances of having to stop are greater due to fast moving traffic which does not need to give way to vehicles entering the road. Because of this, you'll need to look at the speed and distance of approaching traffic and make a judgement about whether you need to stop or whether you can continue without having to put a foot down. If your vision is restricted it's sensible to stop until you're confident of a safe turn. If there is a stop sign, you must stop. Turning right from a major to a minor road Turning right from a major to a minor road Main potential hazards A. Other vehicles attempting to overtake before the junction B. Vehicles trying to sneak past you on the left as you wait to turn right C. People emerging from the junction D. Fast traffic approaching on the other side of the road. Procedure for major to minor road, turning right When turning into a minor road on the right, you will need to cross the lane with potentially fast oncoming traffic and in addition you may hold up impatient drivers behind you. Follow the OSM PSL procedure, use your mirrors, indicate to the right and perform a lifesaver over your right hand shoulder before moving over to the centre of the road. Be aware of oncoming traffic, traffic behind you and road users emerging from the junction. Stop if necessary until a break in the traffic, and turn right being careful not to cut the corner which may inconvenience cars waiting to emerge. Turning right from a minor to a major road Turning right from a minor to a major road Main potential hazards A. Other vehicles attempting to overtake before the junction Procedure for major to minor road, turning right As with the over junctions, use the OSM PSL procedure. Look in your mirrors, indicate, perform a right shoulder life saver check before moving to the centre of the road. You might have restricted vision of traffic before you get close to the junction which means you may need to stop. If there is a stop sign you must stop. Look both ways and be careful of fast moving traffic. Emerge from the junction when safe, accelerate up to the speed of oncoming traffic and cancel your indicators. ====================================================================== # How to pass UK motorcycle module one test URL: https://www.drivingfast.net/how-to-pass-uk-motorcycle-module-one-test/ Category: Motorcycles The module one test is conducted on a purpose built patch of high friction tarmac, and involves a number of cone based exercises. It lasts about 20 minutes, and will be easy if you feel confident with your motorcycle handling. The exercises The course is laid out as shown below - please note that there can be a left or right hand orientation. In this article we'll focus on the 'left circuit' only, but be prepared for the corner to be in the opposite direction. This will look seriously confusing until it's broken up into distinct exercises, which we'll do below. Note that the colour of the cones is representative of what's used in the real test. Figure 1: The full test course 1 & 2 . Wheeling the bike into a parking spot and using the stand 3 & 4 . Riding through a slalom and performing a figure of eight - both of these manoeuvres are combined into a single task 5 . A slow, walking pace ride 6 . A U-turn 7 . Cornering and stopping in a controlled way 8 . Cornering (again) and emergency stop 9 . Cornering and higher speed avoidance The exercises that people tend to worry most about are the U-turn and the figure of eight, but with the right technique these are not as bad as they might seem. We'll go through the detail later in this article. What to do with every exercise Good all round observations and mirror checks before pulling away (every time you have put a foot down) When stationary, hold the bike on the rear brake and put your left foot down on the ground Listen to the instructor, who will talk you through each exercise with the aid of a diagram Ask questions if you don't understand 1 & 2: Wheeling the bike into a parking spot and using the stand The first exercise will be to get on your bike, fire it up, drive into the test area, then come to a stop to listen to the first instructions. Then you'll be asked to ride the bike into one of the parking bays front first as indicated by the green cones ( 1 in the diagram below) and put it on the stand and turn off the engine. Once you've done this, you'll be asked to wheel the bike into the second bay facing outwards ( 2 ). We've found by far the easiest way to do this is to grab the handlebar and the grab rail and wheel the back straight back for about 8 to 10 paces whilst looking in the direction of travel. Then transfer both hands to the handlebars and walk in a U-shape until the bike is straight in line with the parking spot, then transfer one hand to the rear grab rails, walk it in and put on the stand. Congratulations, you're already well on the way to passing! Figure 2: The parking manoeuvre 3 & 4. The slalom and figure of eight The slalom takes off where the parking manoeuvre finished. You'll be asked to get back onto the bike, take it off the stand, start the engine and ride between the first and second yellow cones in a slalom. When you get to the blue cones, you'll need to continue to do a figure of eight until the instructor waves you over to where they are standing (this will be after two complete repetitions). Figure 3: Slalom and figure of eight 3. Slalom Here are the tricks to be successful at the slalom: Take your time. Perform observation and mirror checks before pulling away. Once you have pulled away, do not put a foot down. Keep your knees locked against the fuel tank. Keep the engine ticking over and slip the clutch to control the speed. Gently dab the rear brake if needed to bring the speed down. Be as smooth as you can with all controls. Don't focus on the cones - instead look further off towards the horizon. This is a good trick to maintain your balance at lower speeds. If you feel the bike is going to fall at any time, use the throttle to pull the bike into a more upright positions. 4. Figure of eight For the figure of eight, continue to use the techniques above and make sure you keep your head up and look in the direction you want the bike to go. This is especially important when you transition from left to right steering and vice versa. 5. Slow ride The slow ride (the dotted yellow line below) is simply to get you from the end of the figure of eight to blue cones which signify the starting position of the U-turn.. For the slow ride you'll need to ride at walking pace as if moving in heavy traffic. The trick here is to look towards the horizon, keep your knees locked in, keep the revs up, slip the clutch and dab the rear brake if your speed starts to creep up. Stop the bike with the front wheel in the blue cone gate. 6. U-turn Next is the U-turn. You need to make the turn between the two white lines marked on the tarmac. You'll start with the bike in the blue coned area. When told to do so, do mirror and observation checks and pull away slowly. Before you make the turn remember to do a lifesaver shoulder check. When making the turn, keep your head up and look in the direction you want to go. Once you have made the turn, bring the bike to a stop and put your foot down. The white lines are treated like the curb of the pavement so it doesn't matter if you put your foot down outside the white line. The instructor will then ask you to follow them to the start position for the higher speed exercises. 7. Cornering and controlled stop Remember, you're trying to demonstrate your higher speed control here so no need to be afraid of he throttle. From the starting position, accelerate the bike to a minimum of 19mph, probably using second gear. Head between the blue and red cones at the entrance to the corner, ride around, exit between the blue and red cones. Pass through all the gates, then bring the bike to a controlled stop in the blue box. When slowing down roll of the throttle gently, then use mainly the front brake to bring the bike to a nice gentle stop. 8. Cornering and emergency brake For the next exercise, follow exactly the same route as above, but this time you need to be going at least 32mph when passing between the speed detector marked by the yellow cones. Once you have passed through the speed trap, the instructor will raise their hand to let you know to pull an emergency stop. When this happens, roll of the throttle quickly and apply the front and rear brakes progressively and firmly. Only pull in the clutch at the last minute before stopping. Don't worry about sorting your gears out when you're slowing down, and also don't worry if you stall the bike. 9. Cornering and higher speed avoidance For the final exercise, you initially follow exactly the same route as the previous two exercises, and as with the emergency brake you need to pass through the speed trap at at least 32mph. As soon as you have passed through the yellow cones, roll off the throttle, and steer between the two blue cones. It might look tricky on the diagram, but in real life it is manageable. The amount you need to move the bike is only about 30cm to the left or right. The technique to use here is counter steering - essentially you need to steer the handlebars a small amount in the opposite direction to the direction of the turn and simultaneously move your body weight to get the bike to lean rapidly in the direction of the turn. If you don't already know how to do this - please talk to an instructor! Good luck - you'll be fine! ====================================================================== # Rev matching for motorcycle riders URL: https://www.drivingfast.net/rev-matching-for-motorcycle-riders/ Category: Motorcycles One of our most popular articles in on the art of rev matching, which is a skill which can be even more relevant for motorcycles than cars. This article is loosely aimed at track riders but is also relevant for the road to improve your smoothness and comfort - it also sounds great and is easier on your transmission. If you ride with a pillion and you knock helmets when changing down gears, this technique could be the answer. Read an introduction to rev matching When slowing to a halt this tip is less useful. Bike engines can sustain very high engine speeds - the Honda CBR250 for example could safely rev to 19,000 rpm before it was restricted to 18,000 due to Japanese regulations. When rapidly changing down through the gears while slowing down, as the clutch is released there is a tendency for each shift to force the engine speed to rise significantly, and this can generate a serious amount of engine braking at the rear wheel. A degree of engine braking can be useful when slowing down, but in extremes can lead to jerky forward weight transfers and unsettle the bike - the last thing you need when entering a corner. In extreme cases the rear wheel could lock unless your bike is fitted with mechanical methods of preventing this such as a slipper clutch. Be aware that relying on a slipper clutch to smooth your gear changes is a really bad habit to get into. On a bike, riders are encouraged to move through the gears to keep the engine operating in the power band. As bikes have sequential gearboxes, the risk of selecting second gear from sixth at 80 mph then letting the clutch out is low, however rev matching as each gear is selected will lead to a smoother experience for the rider, and will improve your confidence on the track.So how do you do it? Consider this scenario - you're approaching a corner and are starting to set up the bike. You position the bike correctly, and need to apply the brakes and select the correct gear for a good exit. For simplicity, we'll assume the correct gear is one gear down. You apply the brakes and get the bike to a suitable entry speed to the corner, and before you turn in you select the lower gear. At this moment, it's most essential the bike is settled and stable - so a jerky gear change should be avoided at all costs. Sure, you can smooth out a change by slowly letting out the clutch - but this isn't really a something that's going to shave seconds off your lap time. If you'd like to learn more about cornering, click here In principle, rev matching is simple - as you select the gear and before you let out the clutch, blip the throttle to raise the engine revs. With practice you'll be able to match the revs to the speed of the road and the gear, until one day it will be instinctive. You know you've nailed it when you let out the clutch and there is no noticeable forced rise in revs and the associated weight transfer. As you get better you'll be able to combine all of the actions into a fluid series of events - but as you're learning it may be easier rather than a 'blip' to elevate the revs to a sensible level and hold the throttle there while you smoothly release the clutch - it really depends how rapidly you hope to shift, and how smooth you want to be. Rev matching while braking If you're a confident track rider and you're starting to brake later into corners, you'll need to find ways of shortening the process of positioning the bike, braking, changing gear and turning in. One of the best ways of doing this is to combine the braking and gear changing stages into a single fluid phase. It can be very rewarding to get right and can shave seconds off your lap time. The key is to make sure you can comfortably operate the brake and the throttle simultaneously with your right hand. To do this, you might need to adjust the reach of the brake lever, or possibly buy a replacement. Finger position is really a matter of taste, most riders use their index and middle fingers on the brake and their ring and little fingers on the throttle. Priority should be given to the brake, so make sure you have a good grip and are unlikely to slip off (think potholes). Now assuming you are familiar with rev matching, all you need to do is rev match while on the brakes. This does require a fair amount of coordination, and if your gloves aren't particularly flexible or thick it can be tricky to get right. With practice you'll be able to smoothly flick down through the gears and let out the clutch without a jerky forward weight transfer - the goal is to be as smooth as possible. Depending on your preference and your bike, this can be combined with block shifting to compress the time taken to be fully prepared for the corner. In this case, block shifting means changing down multiple gears without letting the clutch out until the required gear is engaged. Some bikes (and riders) don't react particularly well to this, do worth experimenting and find out what suits your style. Please note, that with all motorcycle techniques, real life tuition is much more valuable that learning the theory online - it's great to understand the principles, but please don't attempt anything you are not comfortable with unless you have been provided with the necessary training and advice. If you disagree with any of the topics we discuss, please stick to the style of riding you're happy with. This is arguably one of the more advanced motorcycle riding techniques, and as a mistake could affect your braking please be sensible and seek tuition. ====================================================================== # Most beautiful cars in the world URL: https://www.drivingfast.net/most-beautiful-cars-in-the-world/ Category: Blog Below is our selection of the most beautiful cars in the world - would you add any to the list? 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