All about Cornering lines

By now, you probably know that attention to details while driving improves the net result. This is again true to all types of driving: Road, Track and Stage -- and to all drivers and driving styles within them. One very important detail is how we turn through the corners. This has various aspects to it and it's the core of performance driving -- the ability to corner at the limit. 

The Basic Racing Line Formula: Outside + Inside + Outside = The Racing Line

Cars don't like turning. It puts each and every component of the car (as well as the driver) under lateral loads that threaten it's stability and distrube it's otherwise plane intercourse with the road. Some drivers try to "help" the car turn by making the turns shorter and take a sharp line to the "inside" of the corner, which makes the corner very short but also very sharp and narrow. 

Others prefer the "highside" -- they turn the car through a very wide arc around the turn, otherwise known as a "rimshine" line. This line suffers from making the corner very long. The real line is a combination of both. Let's take a left-hand, 90-degree angle corner as an example: We approach from the right, "dive" into the corner to "cut" it in the inside (left side) just in the middle of the turn, and than let the car run wide and back towards the right shoulder at the exit of the turn. This allows to make a very straight line because, unlike the two former lines, this line considers not only the length of the track, but also it's width.

On this line we mark three key points: The turn-in, which is obviously where we start turning the car into the corner. The second point is the APEX -- the "peak" of the turn. In every turn, in every line, there is a "peak" where the car is under the greatest load/steering input -- in the racing line, this point is inside the turn, just in the middle whereas in a tight line it would be at the end of the turn. The Third point is the Exit point, where we are after the cornering settle for the next straight.

This line offers to fastest possible speed in the corner. Even if you don't plan to attack the corner at speed, this line keeps you further from the limit and reduces the jerking of the car through the turn. However, it does have cons. I said it was the fastest possible line, but it also isn't. The key is the definition of a corner.

Physically speaking, this line allows for the fastest speed in the corner. However, in terms of driving, real-life corners appear as part of a more complex road: There are preceeding and following straights (or other corners...). In this respect, this line is not the fastest one available. 

The Basic Driving line: In Late, Out Early

The racing line is theoretical, the Driving line is practical. Before a standard turn, say, at the track, we normally have to slow down. When we slow down for the corner, we want to squeeze as much braking as possible into as little space and time. By braking very hard, we are able to keep the throttle full untill the last possible moment and than brake just enough before the turn.

In the theoretical racing line, we would have to ease off of the brake pressure to allow the car to turn into the corner at the required turn-in point. But, if we would place the turn-in point slightly later, we could also brake later and keep full throttle a bit longer on the straight before the corner. The trade-off is that once you turn you have to make a sharper and slower turn. This is worthy because brakes are the strongest means of car control. Since they are stronger than the steering, they produce a greater change in performance.

But, this is still not the essence of the driving line. You brake a bit later and turn a bit later, but you also clip the APEX later, a bit after the geometric center of the turn. Again, this makes you make a tighter, slower turn from turn-in to APEX, but sets you up for a nearly-straight path from the APEX to exit, so you can put more power down more quickely and begin accelerating before the APEX. 

This trade-off is very effective because instead of gaining a few tenths of-seconds in the few metres between turn-in and APEX, you gain several seconds over the several houndrends of meters of the following straight by accelerating into it earlier. This "cornering philosophy" also dictates a very important rule: "Slow-in, Fast-out." You take a sharp line going into the corner, to take a straight line out of it, so you have to weigh corner entry speed AGAINST corner exit speed, in which case the latter almost always wins. Slow corner entry speed + Fast corner exit speed = Cornering efficiency.

This trade-off is very clear in sharp corners. Ameatures are often surprised to find out just how slowly Rally drivers and Track drivers go into the really sharp turns. These ameatures are under the false belief that a skilled driver can enter a sharp corner in a fast speed and this is not true. The limits of cornering speed are the limits of physics, not the limits of a driver's skill.

Another thing to mention here is that sliding the car is not taken very kindly. Any serious sliding makes the tire work in a "slip angle" that it was not planned to function in, and this slows the car down. Sideways is slow-ways. It sometimes happens in rallying that drivers almost can't manage to make it through a slippery gravel turn without sliding, so they prefer to initate a slide intetionally and early, than try to drive without sliding only to slide more sharply later inside the corner. This is a compromise, not a desired situation.

The Last APEX line

The "Theoretical" racing line is called a "geometric APEX" line because it's based on clipping the apex directly in the geometrical center of the turn. The basic driving line is known as a "late APEX line". However, sharper corners demands a later APEX and very sharp corners, especially off of the track -- often require taking a very late APEX which I call the "Last APEX". This apex should be late enough to provide an almost straight driving line through the exit of the turn.

The last apex is not your usuall line because it makes turn-in so sharp that it's often not desirable in spite of the fast exit speed. This line forces you to "rock" the car into the corner by a relativelly rapid turning of the wheel to make the car to change it's direction at once (where in the other lines the car is progressively eased in towards the apex) from turn-in towards the APEX. However, it is advantagous in very slow bends, and in other conditions when it's required -- it keeps you prepered for what's coming next by allowing you to have a better look around the turn in advance and by giving a slow and safe turn-in and a steady state inside the corner.

This is a good place to define the relationship of the three points that make up a cornering line: Turn-in, apex and exit. We have already attributed the greatest importance to the exit -- it has the greatest effect on performance. The apex is significant for being the place where the greatest load is placed on the car. The turn-in is important because it initiates the turn. In order to exit a turn properly you first need to enter it, and properly.

In fact, we can say that the first 20% of the corner (=turn-in) make up for 80% of the cornering, but that the results of those critical 20% are only discovered half-way through the corner (at the APEX) and the net result is only experessed after the exit. Races are won over the straightaways.

The error line: Early APEX

The problem with "Slow-in, Fast-out" is that you first reach the corner's entry before you do the exit. Without planning in advance (by looking ahead), a driver is going to prefer fast entry speed anyhow. Because of the high straight-line speed the car is in, the driver is likely to try and smooth the corner by turning in from an earlier point and in a line even more straight than the geometric apex. However, cornering lines have some sort of "racing karma" to them -- a earlier, smoother and faster line at corner entry, will become into a tight and slow line at the corner exit. You will simply clip the apex too soon, and the car will not be in one line with the exit point, and would instead be facing the edge of the roadway, forcing a slow down.

If the driver's attempts to slow down are succesfull -- the real trouble begins. The driver might interprate this as a succesfull corner, without noticing that trying to be fast in entering the corner have made him to slow and brake on the straight where he should have been on full throttle.

A summary of Driving Lines:

1. Early apex: This line is normally an error. The driver turns-in too early, which lines the car up towards the edge of the turn after the apex. This sort of line sacrifices corner exit speed for corner entry speed, which is foolish.

2. Geometric apex: This line is fast but not very commonly used. It offers a very smooth line by clipping the inside the corner directly in it's middle, but it does not offer a very good corner exit speed.

4. Late apex: This is the normal driving line. You turn-in and apex later to achieve both later braking before the turn and earlier acceleration out of it. You sacrifice corner entry speed for corner exit speed, which is the best tradeoff there is.

5. Last apex: Popular in road driving because it enables to have a better look around the turn. Might require turning the wheel somewhat sharply in racing.

"Taking a Set"

At the Apex of the turn, the car essentially becomes a bike. After turning the wheel, the car's weight is being transferred to the outside wheels so they provide almost all of the cornering force. This is important because the "inside" wheels often become nearly fully neglectable. This enables to cut the inside of the turn so much that you drop the inside wheels off of the pavement. On the track, this helps in making a faster turn. On the road, the same ability can be used to avoid a car that strayed into your lane or to get around slippery parts of road that you find inside the turn (a puddle, a sheen of ice, an icy patch).

Sometimes, especially when you take a "last apex" into a very sharp corner, a relativelly sharp steering input should be made to make the car respond by "taking a set" earlier. This rapid turning of the wheel rocks the car somewhat, distributing the weight of the car on the outside wheels when slightly more biased forward. Another place where quick steering inputs are required is in some of the fast curves on the track. Some curves of the track are very fast and you accelerate all the way through them, but sometimes they are performed at a speed and/or over a surface/incline that makes the car push too much out of the turn, in which case rapid steering helps.

Camber and Castor

Camber and Castor are two principles in wheel alignment. Both of them change the way in which a given tire faces the road. However, the road also has a Camber and Castor. The Camber of the road, is a side-slope while the Castor is the uphill/downhill incline. Each of the two carries an effect on the driver, car's grip and car's handling.

Negative Camber is the classic example and it is seen on the road and track, particularly oval tracks, where the corner appears to be "banked" and inclined towards the inside. This is "negative camber" which helps increase the car's lateral grip. Think, if the corner was banked at 90 degrees, we would not have to turn the wheel at all. It keeps the car's weight lateally stabilized. In a negative Camber corner, it's vital to be smooth and gentle because the effect on car handling is a reduction of understeer. This also dictates that the driver should take the geometic line and sometimes even an early apex line.

An uphill incline has a similar effect on grip, but increases understeer by causing a weight transfer to the rear. A downhill incline would decrease the grip levels. The problem is that Camber and Castor are not nessecarily identical all the way through the corner. Some corners have an increasing Camber that makes the driver turn-in early, while other corners have a decreasing camber, where you want more turning effort done in the early, grippy part of the corner, and less in the final part of the corner. 

Banking also carries an effect on the effect of grip reducing agents. If a part of the road is inclined, water and foliage would drain downwards, forcing the driver away from the inside edge of the corner. In fact, the road always have some camber that drains water sideways, so the edges of the road are categorily more slippery, and it often makes the driver adjust the line so that he does not turn so far from the edge of the track.

Corner prototypes

The track has three corner prototypes: A fast curve, a moderate bend ad a slow corner. The fast curve is the most simple but treacherous sort of corner. The line is normally geometric: You turn in and apex just in the center of the turn. Usually, some acceleration takes place all the way through the corner. The driver has to turn the wheel smoothly and once a steering angle is established, the driver controls the line by throttle maintainence -- more throttle will induce more understeer and a wider line. Less throttle would make the car tighten up the line.

Lifting-off completly usually undermines the car's stability and can lead to terminal understeer that has to be coped with by strong and instantanous acceleration without significant steering corrections. Steering corrections will rock the car, but the speed reduces the engine torque enough so that, in all drivelines, it's possible to use more engine power for recovery and less steering. In a fast corner, staying "at one" with the car obligates that the driver keeps his eyes high, usually all the way through the corner.

Sometimes, fast curves are very fast but due to the line, incline and/or car -- create too much understeer that threatens to push the car off of the right line. These turns might also require a quick turning input for "taking a set" earlier.

The moderate-speed corner is the normal racetrack corner. It is slower than the fast curves and does not allow to accelerate all through it and usually requires braking before it. The line is therefore -- the basic late APEX line. This corner requires finesse like the fast curve -- and a minimum of weight transfer -- but requires some decisiveness to get around nicely. You brake to reduce your speed in a straight line. As you turn in, you remain with brake pressure applied and "share" the tires' traction between cornering force and braking force. This is known as "brake-turning."

You start easing the steering into the corner as you start easing the braking force off -- the more steering, the less braking. from full 100% braking, you switch to 90% braking and 10% cornering force, and than to 75% braking and 15% cornering force. Once the full steering angle is achieved and the maximum cornering force is established -- you have to seemlessly lift off of the brakes and roll onto the throttle just enough to keep the car at a constant speed so that it's just cornering. This is called "Balanced Throttle." 

Just before the apex, the car is lined up so that you increase balanced throttle to some acceleration and than, at the apex -- start to unwind the steering as you accelerate. This is the exact opposite of what you do with the brakes as you turn in -- the more steering you unwind, the more throttle you can apply. From 100% cornering, you go to 95% cornering and 5% acceleration, 70% acceleration and 30% acceleration up to full acceleration even before the straight. 

Throughout the corner, the car has to behave around neutral -- either fully neutral or with slight understeer. If the car understeer, the driver needs to reduce speed and/or acceleration. Just slightly back-off of the throttle or brakes while you undo some steering. The car would regain grip faster and more smoothly if it only has to make up for extra 3 degrees of steering instead of 5 degrees, so straightening the wheel slightly helps. Once regripped, you can turn back into the corner. You actually saw the wheel slightly out of the corner and back inside. 

If the car oversteers, the corrective input has to be faster and car-dependant: In a Rear-wheel drive and/or four-wheel drive, you will need to apply constant throttle and use the steering to balance the car. You actually need to reduce the steering angle and probably turn the wheel away from the corner (countersteering) and than straighten the steering back once the car is balanced. In a front-wheel drive, you need to recover early enough that you don't need to countersteer -- you just accelerate forward and start to straighten the wheel. The key in both cases is to to keep the eyes up to the next reference point.

A Sharp corner is not very common on the track. They are more common in rallying, especially road rallying, as well as in normal road driving. The apex here is even later and the braking is drawn ever deeper into the corner. You keep the car braking in a straight line a bit later and than begin to turn the wheel quite sharply into the corner while lifting off of he braking a bit later but less progressivelly. You set-up the car for the "last apex" and keep the constant throttle towards the apex, and accelerate just through it and out of the corner towards the outside. 

Understeer and oversteer recovery are quite similar, except that some front-wheel driven cars can have enough torque in such a turn, that it can be utilized to help straighten the car out of oversteer. You start straightening the wheel while momentarily accelerating hard to spin the front wheels slightly. This spinning still allows some acceleration to take place, so there's still a rearward weight transfer that helps the rear grip again, but the sliding of the front wheels will cause them to slide outisde and straighten the car instead of countersteering. Once the car is straight, you reduce the amount of throttle to get you around the turn.

Successive corners

Let's assume a place on the track with one righthander followed directly by a lefthander. You stick to the left before the first corner, turn right and into the corner, apex and track out to the left again -- this would place you on the "inside" of the next corner and off of the right line. This is particularly bad because our priority is for corner exit speed, so the speed coming out of the last corner in the corner-set is most crucial.

The choice is to "prioritize" the second corner. You take the "last apex" line into the first corner, which enables you to keep the car "pitched" on the inside after the apex, allowing you to take the correct late apex line towards the next corner. Alternativelly, if you have two right-hand turns one after the other, you can take the first corner with a geometic apex and than track-out to the far left-end of the road so that you can carry a late apex into the next corner.

This is just theory. In real-life you sometimes don't track-out all of the way, and negotiate the following corner somewhere from the middle of the track. This is mainly true for the faster curves that are in times very easy to get around even when you don't use the whole track width.

On the road

Driving lines on the road can be used in one of two causes: To increase safety, or to increase speed while practicing racing lines in winding roads. The system is preety much like the lines used in a race. Fast curves normally have a field of vision which is open and wide around the corner. This enables to use the geometric apex to make the corner as smooth and grippy as possible. Of course, the line on the public road should be restricted to the bounderies of your own lane.

A moderate bend is the type of corner you might negotiate on the countryside rural roads and in winding mountain roads. On the road, we need to drive well within the car's grip limits, so the main problem in such corners is not the grip that gets us through it, but the limits of vision. This is why a late apex is very effective here. In fact, it's best to take an even later apex -- just like the last apex. Still, because we drive on the public road, we need to avoid the sharp steering input which is used in that line: You turn the wheel a bit earlier and bit more smoothly, but aim for the same "last apex." Sharp corners are negotiated in urban districts and in mountain roads. These corners are negotiated much like the moderate speed bends: You enter it very slowely, wait to a very late stage and turn the wheel into the corner. You try to be smooth, but sometimes smoothness has to be compromised for a clasic "last apex" line. 

On the road, it's important to reduce the overalp between braking, steering and acceleration. Some overlap helps in achieving a weight transfer that makes for a bit of extra responsiveness of the car during transients. However, less overlap makes for easier, safer cornering and a larger grip reserve: You brake with feel in a straight line, turn the wheel smoothly (but as decisivelly as required) and ease off of the brakes. You than establish balanced throttle all the way through the turn. Even when you start winding the car through the corner, you don't accelerate much -- just a little bit of acceleration to help straighten the car.

On the road, very fast curves and very sharp and slow corners often require a different line than the above prototypes: Let's say you drive on the righthand lane of the highway and you follow a slight curvature of the road to the right.  Moving to the left-edge of the lane is going to be really unnessecary. It's going to put you out of the normal position you should keep on the road -- so it's best to stay on the right or maybe move just a bit towards the middle of the road as you turn. The same happens in slow, sharp corners in the city -- you keep a tight line to avoid posing a hazard for motorcycles.

Even in corners where you do take a wide driving line you don't nessecarily use the whole width of the lane. In a righthander, you want to keep a short distance from the divider line to keep a certain gap from oncoming traffic. Even on lefthanders (in countries where you drive on the right) you can't always set-up from the rightmost edge of the lane, because it can be slippery due to dirt and especially when wet. 

Eyepath

The eyepath is a major element in taking a corner properly. First, you need to drive straights with your eyes UP. This way, you will see the corners in advance from the largest possible distance. Once you see a corner, you need to to glance into it and as far as possible through it. You need to assest the corner's type: What type of corner is this? The next step is to visualize the cornering line you want to car to take through the corner. Once you established the line you want to take, you mentally draw the turn-in, apex and exit points on it.

While glancing around the corner, look out for the convergence point. This is the furthest point of the corner you can see. This point appears as an arrowhead that seems to "unwind" and get away from you as you get closer. Adjust your pace to fit to that of the convergence point - so that you can match the right speed, gear and pace for the corner. 

Once you enter the corner, you use your eyes to guide you through the right line which you planned and visualized in advance. In fast curves, you just treat the corner as a twisting of the straight, and keep on looking through it. You don't even need to use the convergence point. On slower corners, however, a more advanced eyepath is used. You start driving towards the convergence point. You set the right speed and gear to the corner and adjust your position in your own lane so that you are ready for the line you want to take.

When you reach the point which you designated in your imagination as the point of "turn-in", you should evert your eyes and look towards the next point -- the designated apex. You should gauge the exact turn-in point through the corner of your eye, through your peripheral vision. As you start lining up towards the apex, you look through it and down the following straight. You gauge the exact clipping point based again on your peripheral vision.

On the track, you improve this system by using a system of reference points: You set permenant visual details as points where you want to turn-in, apex and track-out. Apart from the fixed points, you use you judgement to gauge when you brake, when to let up the brakes in a corner and when to begin accelerating out of the corner. The driver can also use his steering and engine/exhaust tone as points of reference. 

Lesson learned:

For the next month, try and practice the effective driving lines: Both road driving lines and race driving lines. You can also practice racing line on the public road too. They are best practiced on deserted winding mountain roads. You first make a slow run and inspect the whole road and decide what is the right driving line and if there are any surprises to avoid. Than, you do a faster run with the right driving lines.

Automtive maintainence -- Tyres

Tires are the number one aspect of car maintainence. They form the single contact of the car with the road. You can upgrade your brake lines, brake fluid, brake rotors, calipers, pads and discs. You can bleed and bed the brake system. You can stiffen your springs and dampers, lower the car's ride height, change your wheel adjustment and improve the steering mechanism, install stiffer anti-roll bars and brace the chassis. You can turbocharge the engine and swap the motor oil and change for lighter rims and more aerodynamic downforce -- but all of these combined will not be as good as a nice tire. Because the tire is the only contact with the road. If you cannot put all this extra performance down through the tire and against the road -- it is insignificant.

Understand, brakes do not slow down the car or stop it. They slow down the rotation of the tire, and the tire slows down the car. The same goes for acceleration and steering and to a certain degree -- for dampening. Hence, driving on bad tires is like driving with a faulty brake system. In fact, modern brake systems have turned so reliable that they never fail completly, so you always have at least some precent of pressure that can still be sufficient to get home. Tires, on the other hand, wear quickely and can give you the same result you might attribute to a failure of the braking system.

The problem is that the tire's contact patch which is pressed against the road is quite little, quite like a man's footprint. See for yourself: Take two pieces of paper and put them in front and behind a tire. Try and get them closer to one another by sliding them under the tire. At a certain point, the paper sheets will meet resistance untill they could no longer be pressed under the tire. The gap left between them -- is the area in contact with the road. This little patch of rubber, is even smaller because road tires (and most tires used in racing street cars in circuits) have a tread that means that some of the rubber in the area of the patch is not on the ground at all. 

So, this little patch, made of nothing but rubber, has to accelerate us (and keep us in a static speed when cruising in highways), slow us down and stop us, turn us aside and keep the car is the requested direction while resisting the side force, dampen bumps and carry the weight of the car and it's passengers/luggage, sustain pressure, physical forces, bumps and heat, divert water, dirt, snow and other things from the way, give feedback to the driver, etc...That's a lot of effort in a day! For instance, on the wet, the tread of the tire has to clear significant amounts of water which, in highway speeds, can be more than one gallon per second!

I have seen cars that stopped significantly further away in emergency braking tests, spun while braking and/or cornering, were not responsive to driver's inputs, very uncomfortable to drive, and produced bad tire and gas milleage -- all due to bad tires in particular. Tires are involved in more car crashes than any other part of the car -- it's not a stuck gas pedal or faulty brakes that could kill you, it's worn tires! Whether they explode, peel off or simply not stop you fast enough or get you into a slide, tires equall safety and bad tires make the car work against the driver.

Tire Choice

Tire maintainence begins with the choice of the tire. There are differences in qualities of tires. For road drivers, the basic parameter is the manufacturer: It should simply be a tire that is made by a known Manufacturer. Here are some examples: GT-Radial, Continental, Bridgestone, BF-Goodrich, GoodYear, Pirelli, Michelin, Falcen, Toyo, Kumho, Yokohoma, Dunlop, Maxis, and others.

Other aspects of tire choice involve the tire rating and type: Tire rating, like all the data regarding a certain tire, are printed on the sidewall of the tire. They rate Temperature, Traction and Treadwear. Each of them is rated between A (or AA) and C. Treadwear is rated in figures. You should go for anything above C. The "Traction" rating in particular, relates to how well the tire stops on the wet -- which might not offer a good indication for how good it is on the dry, so a tire that has AA traction, might be just as good as one with A or even B -- on the dry. Treadwear states how quickely the tire is being worn. Basically, softer rubber wears out faster, but gives more grip. Therefore, drivers who do not make long trips, can go for tires with relativelly soft rubber that give more grip but less treadwear. Treadwear should never go below 200.

The type of the tire relates to it's function: It can be an all-season tire, a winter tire, a road tire with M + S (mud and snow) rating, snow tire,  ice tire and racing tire. Do not drive in the summer with winter/snow/ice/mud and snow tires and do not drive in snow/ice with allseason/race tires. Do not drive roadcars with race tires. Generally look for anything written on the tire with the word "Performance" on it -- these are normally very good tires. In freezing conditions, look for a sign of a mountain with an ice flake inside it -- stating that the tire is adecuate for heavy snow.

Good tires don't come for free but overall, tires are one of the cheapest car parts and the most important -- so changing them to new tires will actually pay out quickely in terms of milleage and in avoiding collisions. Remember, the tire should come from a known manufacturer, have good ratings and be suitable for the conditions.

So, we have bought new tires, but what about their placement? You have probably heared the rule of  "placing the good tires on the rear." The goal of placing the good pair of tires on the rear is to avoid the car skidding into a situation called oversteer, where the car skids with it's tail and spins around. This happens when the rear wheels have less grip and slide first. So, by placing the good tires on the rear, we avoid oversteer. There is also a school of thought that is for placing the good tires in front -- mainly because that's where the bigger brakes are. 

Our advice is simple: The good tires go...ON ALL FOUR WHEELS. If there is a doubt as to where to place a new pair of tires, this means that at least two tires are already worn to a point where still riding on them is perillous. When you have such a doubt, now is the time to replace all four tires. This way you get both a stable car that does not oversteer, and also good braking -- and not for a significant change in the amount of money spent.

Tire Replacment

By now we have covered the subjects of purchasing new tires and placing them on the car's wheels. But, there is more to it. First, we begin with when to REPLACE tires. There are several criteria, and since tires are both relativelly cheap and very crucial for safety and performance, we should be strict and if any single one of these criteria is present -- we should replace tires:

- If the tire appears significantly worn, damaged or dry -- we should replace it (no matter how much it has travelled or how old it is). Before every drive, take a few second, to look at the tires and search for cracks and damages.

- If the tire has did a sum of 70,000km, it's time to replace it. Even if it still looks good and new, and even if it is still new -- this tire has probably lost over 50% of it's abilities.

- It the tire has passed the age of three years -- it should be replaced. No matter how much miles it did (even if it wasn't used at all) or how good the tire appears to the naked eye -- the rubber undergoes a process of expanding and shrinking under weather changes and it also dries out -- making the tire lose some 20% of it's qualities already when just two years old, and about 50-60% when three years old.

- Tire Tread Depth: With all but Slick racing tires, the tires should have a deep tread for any moist the tire might come in contact with. The popular penny test indicates that the tread depth is larger than 1.7, which is just above the legal minimum of many countries. A safety criteria is a minimum of 3 mm.

A tire's age is determinded based on the date that appears on the tire. It is the only date that in printed INTO the rubber. It usually consists of a letter, and than four figures. For instance, 2610 -- which stands for the 26th week of the year 2010. 1709 stands for a tire that was "born" in the 17th week of 2009.

Tire inflation

Now we reach the most complex subject of all of these, and none-the-less important than the above: Tire air pressure. Tire pressure is measured at PSIG or BAR. I will use the PSIG measurements I'm used to. They represent the pressure created by the amount of air which is squeezed into a tire. More air results in more pressure and less air -- in less pressure. When referring to tire pressure, it's important not to associate it to baloons. In the tire, air pressure has a much more crucial structural role: More air means a stiffer tire and less air means a softer tire.

If you remember, I previously mentioned that tires made of softer rubber have more grip but wear out sooner. But, when we look at the tire as whole, things are bit different. The side force generated when turning the car works on the tire, distorting it somewhat. A stiffer tire resists the side force and distorts less and can provide more grip and less wear. That's why the fear of the tire exploding if we overinflate it is not justified -- unless the tire is extremlly overinflated.

Tire pressure also changes the shape of the tire. Many people believe that less pressure will make the tire scrubb against the ground which means more rubber against the tarmac which means more grip. This is not a true assertion. Why? Because it is made based on looking on the tire from the outside. If we could look on the tire from below (say, if the tarmac was transperent), we could see that -- because less air means that the tire is softer and flexes more -- it is pressed agains the surface but it also flexs and folds so that the center of the tread -- where most grip comes from -- is folded and lifted from the surface. This is catastrophic for grip, tire wear and especially for braking. 

On the contrary, overfinlation below the "right" pressure, results in the opposite. The tire, which recieves a convex shape when underinflated, is now rendered into a concave shape, which makes it grip the road with the center of the tread, and not so much with the shoulders of the tire (corners of the tread). This is better because the center of the tread is both more durable and more grippy, and also in adverse conditions because this kind of tire tends to penetrate through water, snow, mud, gravel and whatever might cover the road surface, and find grip below. If in doubt, overinflation is better than underinflation!

Note: Many people believe that off-road drivers tend to underinflate their tires. They do not! In off-roading, underinflation is used in very specific situations, like deep mud or dune driving (driving on loose, dry sand). In this case, the convex shape of the tire captures sand inside it which gives it more grip. In shallow mud, mould and alike -- the underinflated tire will capture the mould of mud in it's folds -- which would make it slide over them rather than grip the more grippy earth beneath them.

But, why should there be any doubts regarding tire inflation? After all, the manufacturer states clearly how much pressure to put in each tire. This is all very true, but some variants change the pressure:

1. Heat: After driving on tires to the gas station, the tire sometimes heats-up considerably. If you feel noticeable warmth when you touch the tire's sidewall -- it is hot and the air inside it has been expanded by the heat. Say that the pressure in the tire before you started to drive was 30PSI. In the station you might reach a measurement of 33PSI. Now, let's say the tire is undefinflated and only has 26PSI, at the station this might appear as 28PSI, and you will have to inflate it to 33PSI instead of 30. This is another advantage of overinflation -- you can always bleed out the excessive air later.

2. Load: Three healthy adult passengers in the back seat increase the weight of the car significantly. For such cases, you will find that the manufacturer specified different figures for inflating the tires when the car is loaded. Inflating tires with more pressure for a loaded car is something most people fail to do, but it is very important, especially in long trips, and it severly reduces the grip of the loaded vehicle.

3. Performance: In racing, you deduct the correct pressure in the practice sessions. After a few laps, you check the tires for wear and temperature. If underinflated, the contact with the road will be in the tire's shoulder, so it will be more hot and mor worn. If overfinflated, the heat and wear would be more evident in the center of the tread.

4. Accuracy of the check: Different guages give readings in different accuracy. The least accurate kind was/is used in old gas stations where the you aim the pressure you want with by rotating a dail. These pumps should never be trusted (they can mislead you by more than 10 PSI!). Most modern gas stations have digital guages that are more accurate, but it's still advisable to use a personal guage. Pencil guages are the least accurate type of personal guage, but they are cheap, easy to carry around and resistant to blows -- so they are my choice. 

Digital guages are more accurate and some dail guages are even more accurate -- but the differences here are very slim and these guages are cost more, harder to carry around, and can be knocked out of callibration by a blow without you even knowing about it. A pencil guage will mislead you by a maximum of 0.6 of a PSIG.

The frequency in which we need to check air pressure is in times considered as once a month. But this is too much. It's best to check once every two weeks. This way, there is no need for dramatic inflation, and the whole procedure takes a few seconds, faster the fueling the car. Remember to put the caps back on the air nuzzle once done!

If we rate the different parameters of a tire, the most important is wear, than comes milleage, age, tire quality and tire inflation, but the differences are not very significant.

Front tire failure

If one of your front tires do fail and blow-off when you drive, it's important not to panic. You can still control the car.  Slow down steadily and keep on steering the car carefully at a low speed. Some states in America and Europe have special stop-zones alongside the road where you can stop. If the road does not have such a stopping point -- DO NOT STOP ON THE SHOULDER OF THE HIGHWAY. The risk is like nothing you ever experienced. Get on the shoulder and drive slowely enough so that no significant damage be caused to the rim, untill you reach a safe place to stop. The risk exists even if the blown tire is on the side of the car which is not facing the road.

Rear tire failure

This can cause a spin-out that is usually beyond the ability of the driver to control. The choice is to brake really hard to stop the spin, and try and get to car slowely to a safe stopping zone.

Driving Styles and changes in Technique

As you have probably witnessed by now, effective driving on the road or track, is based largely on proper technique. In particular, race driving in a track revolves around the ability of the driver to perform ideally in the ideal technique. Without enough seat time, reading the theory of these techniques can create a mirage that developing a driving style is performance limiting.  After all, on a track, we need to strive to be driving at100% of perfection, which does not leave much room for different style, right?

But, saying this is merely a result of not having enough seat time.  The seat time makes the driver aware of the difference between theory and practice, between our current reality and the desired outcome. The seemingly slim but surprisngly large gap marked in the word "striving to perfection". 

Racing Spartanism

Activities of popular sport have created the illusion amongst ameatures, that in any sport -- and motorsport not being an exception -- the participants rely solely on their skill. So many enthusiasts with basic awareness to vehicle handling, are under the false belief that race-cars are set to oversteer so that they could turn really well. They fail to understand that all racing drivers are in fact just people. There are very well-defined bounderies as to what they cannot do. No driver, not me, not you, not Michael Schumacher, Sebastian Loeb, Colin Mc'Rae or Ayrton Senna -- none of the above can:

- Enter a corner fast (fast as in -- above the maximal corner speed)

- Control sudden oversteer when driving the limit at full speed on the track.

With all do respect for skill, it is not the only thing drivers, even expert drivers, rely on. No driver (except for Colin Mc'Rae) would trust solely on his skill to drive a car that naturally oversteers. Yes, they might manage to drive it, but they prefer not to. They adjust their cars with some minimal understeer, for reasons of efficiency, but also for some safety and consistency. Do not confuse these with either fear or hesitation. A driver that adjusts his car so that his consistenty and safety rely solely on his skill -- should never set-up cars!

Another example is the point of Skid Recovery. I have already expressed myself again short tuitions that pretend to teach a driver about Skid Recovery. It is a fragile and problematic field: Average drivers cannot acquire true skid recovery skills, but expert race drivers also find themselves lacking the need to apply it: Either they avoid it, or otherwise they find themselves reaching a state of skidding at a speed and pace that do not allow to recover. Skid recovery is a practice mainly for drivers in the broad midrange of skill, and even than -- prevention preceeds correction.

Furthermore, it's easier to learn how to slide than it is not to slide. Many drivers find it easier to have the rear wheels turn them into the corner and use the front wheels as a "stability control" of some sort. It also gives a sense of fast driving through the feeling of the jerky car and the constant application of steering inputs. In a certain way, this is what rally drivers do on gravel -- the slide not to reduce safety, they slide to increase it. If you drive the limit, any small mistake leads to a sudden, sharp breakaway of the car at speed. If you drive within the limit, intentionally provoce the car into a slide and control it through the slide, you will remove the element of surprise because the slide is intentional and you will get a more controlled slide because the speed and pace in which you initiated the slide are reduced.

To quote Ross Bentley: "The most succesfull racers of all time, people such as Jackie Stewart, Alian Prost, Al Unser, Rick Mears, Richard Petty and Dale Earnhardt all have one thing in common -- they finish races...Never forget: "In order to finish First, first you have to finish." In racing, playing safe is playing smart and playing smart is driving faster. 

In fact, if you remember my modell of Effective Driving -- where Safety is just one of the byproducts of good driving habits, the above statement still hold true. Even though the goal of effective driving is to give you not just safety, but also milleage, comfort, etc. I always stress those benefits because I don't like it when certain people neglect them by talking just about safety and/or speed. Still, I have to agree that safety is the main concern: If you concern mainly or largley about things like comfort or milleage, than you live in an illusion of safety -- and you think you are safer than what you really are. Safety is your number one concern, period.

Professional Training

I believe that, in a certain way, the popularity of motorsport (or any other sport) stands in contradiction to the level of professionalism amongst begginers: In the US and in several regions of Europe and the UK, track days have become so accessible that driving around a track has been degraded from the prestigious status it once held. By itself, there is no problem with this. In fact, it could have been great. The problem begins with groups of people in different levels of skill -- which are "autodeducted" drivers.

Driving is an activity with very strong psychological aspects relating to one's independence and freedom. We, as drivers, thus search for autonomous improvement: We want to get better on our own and we admire those who we think have succeded in that path. Psychologically, a driver that "grew up" himself as either a road driver or a race-driver, gives the same impression as modern buisness man that came from a poor family and made himself into what he is today. 

My point is to challenge this school of thought. The basis of this way of thinking is that we favor innovation -- we like making NEW things, we like doing things differently than we were taught. However, maybe imitation -- following the lead of a person that has earned our respect and appreciation -- is not so bad. Maybe it's even honorable for people to follow the lead of those who they themselves deem as "professionals"? Well, if you ask an anthropologist, he will tell you that whether you judge imitation to be worthy or not, it is very widespread. Much more common than most people believe. The fact is that most human actions and decisions are made based on imitation and not based on someone's personal ideas and judgement. Many historical cultures, some of which are considered to be very glorious, attributed imitation with a high degree of respect. Only our culture, the modern culture, has started to question imitation and favor innovation instead. Over the human history, we are the exclusion and the exception, not the "normal" people.

Furthermore, this modern perception has little effect on the actual reality. Relating to driving and motorsport as a part of the field of sports, we can safely say that people get into the world of professional sports and advance therein, through some training with instructors, coaches or whatever you would call them. They provide a third-party point of view which is crucial at initial stages and maintains it's significance as the student improves. You cannot teach yourself Tennis, Swimming or performance driving. Well, you CAN do it, but the result might not be very good.

The problem is that without professional observation and training, the driver is not likely to even distinct "good" from "bad". He might do something very badly, or at least not as good as he can do it, and not being aware of it. A driver simply cannot measure success by himself. It's not that he nessecarily won't succedd, but if we define success as a goal, we want as much of it as possible. As I say, we don't want to go FAST, we want to go FASTER. Even competing race-car drivers can spend a career of driving with several basic technical mistakes in their driving style. For something to "work" does not mean it's working as efficiently as possible.

What I'm getting at, is that there is no lost in dignity when someone turns for a trainer to work with him on improving his driving, and there is not lack of dignity in taking procautions, even on the most competitive track enviornment.

Vehicle as a Varient of Technique
The question is whether other cars demand another technique. The short answer is yes. The basics of effective driving are/should be shared by all drivers in any enviornment/car. In the level of a personal driving style, the car carries a considerable change, in terms of driveline, weight distribution and suspension geometry which have an impact on the variant of DRIVABILITY.

Drivability is the criteria for how well a car drives. Unlike the question of how much grip or power it has, drivability is largly subjective. Certain cars benefit from drivability which is better in certain respects over cars which are superior in different aspects of drivability. One car might handle with greater obedience to the driver, but another might have superior communication with the driver.

Some cars demand more accuracy, some demand more smoothness, some demand more decisiveness. Some cars demand more input through the throttle/brakes and are literally driven with the feet, other cars might have a balanced that is slightly more inclined towards control through the steering wheel and the driver's hands. A driving style, whether in relation to a different car or a different person, is not in the big picture (and is therefore not crucial for performance). It's about the perception, it's inside the driver's head: it's where he places the stress. It's a manner of perspective: Let's say that an effective turn-in requires turning the wheel at a certain timing and pace. One driver might view it as being a relativelly "quick" turning of the wheel, while another driver might turn the wheel just as quickely and relate to it as being "slow" and "smooth" relative to something.

Driver as a variant of performance
A known American driving trainer, named Peter Krause, has a saying: ""The driver is the greatest performance variable in the high performance driving equation"." If there is a thing that can be said with certainty in the field of racing, it's this saying. Driving skill and good driving techniques (which are adopted by training with a trainer) are better than any car improvement. A bad driver will mess the ride in the best cars. In fact, the rule states that the faster the car, the slower is it's driver. Performance cars, and especially professional racecars, are very hard for ameatures to drive and will not see mistakes kindly.

In French Racetracks, the local instructors often have the tradition of taking students between sessions to a lap of the track with a Van. The point of such a lap is to allow to carefully inspect parts of the track that are hard for the students, by driving the track more slowely, but it also has anoter purpose: To show that car control and effective driving at speed are possible in every car -- all that has to be changed is the driver's attitude. This brings us back to driveability: Some cars are more difficult to drive effectivelly, but can be more rewarding, some cars are easy to drive fast, but can be less rewarding, and some are both easy to drive and rewarding. I have witnessed very impressive car control skills practiced in vans, trucks, trailers, old roadcars, etc.

Still, there are other levels to be considered:

1. The car: Like I said, racecars should be adjusted or performance, but allow for a certain margin of error. If you don't give yourself that extra safety gap, you are not going to be driving fast. In fact, you risk the chance of not being able to drive further at all.  Likewise, driving skill should never be used as an excuse to drive in a badly-maintained vehicle. A good driver only drives on a car that let's him drive effectivelly. If the car has worn or old tires, it will work against the driver.

2. The road: My point that limiting performance to allow for a margin of safety is legitimate, is tenfold more important on a busy or slippery track, or in places of high speed, small runoff areas and surely on the public road. Trusting solely on your skill to keep you safe while not paying attention to the changing conditions is simply dumb. We are humans. Humans naturally make mistakes. Know your limits, on the track and off of it. Even on the track, in order to drive fast, you need to know WHERE and WHEN you can drive fast. The Nurburgring is a place where a "smart" driving style pays off. The Nurburgring is not a racetrack, it is a ROAD, and has the safety runoff areas of a road. There are various areas and situations where you CANNOT drive fast.

3. The road users: They can be related to as part of the road. This is especially beneficial in competition, but less beneficial on the road where other road users interact with you. For an example, we know that the winter and rain present hazards for us, but other than being more dangerous and difficult to us, do we consider how much more difficult is it for the other road drivers? Think, other road users are probably as challenged as you, making them less likely to notice you, maintain the nessecary safety gap from you, etc.

Getting back to Driving Styles

So, one driver turns the wheel more sharply, another turns it with a stronger stress on finesse, without either of them being just balanced as they should be. However, before criticising them, understand the torment of sports -- no matter how much you constantly strive to perfection, perfection is not hard to achieve, it's impossible to achieve. The idea is to get as close to it as possible, which can be done in several ways and from several directions. The differences appear slim to the ameature, but mean a lot to the experienced. The only way to discern them is to have practical experience and, based on what I said before, such an experienced better be with a trainer. 

N. B. If you like conspiracies and you believe that I'm cynical and all I want is to get money out of you -- you can be certain that I'm not instructing driving anywhere near you, so I have absolutly no financial gain from what I write about driver's training. I simply believe in it, as a trainer and as a student.

The Skid and How to correct it/ Ross Bentley

Most skids, spins or out of control situations are a result of loss of concentration, driving beyond the limit (too fast), or a simple mistake (which usually upsets the balance and traction of the car). Getting into this kind of trouble is quite easy, especially in adverse weather conditions. And getting out of it can be easy with a little knowledge, some thought and experience.

Skid control is never easy. It is one of the most complex aspects of car control there are. It is in fact a self-contradiction: Skid-Control involves regaining control that has been lost. Knowledge and thought are always good, but during a skid, they are near completely useless. I have seen drivers who have just been practically beaten for a hour with knowledge regarding oversteer, what to do and what not to do: They set out to the SkidCar. It's not their car, there are no obstacles in sight, only open area of endless grippy tarmac, the driving speed is slow, the driver is in a “triggered” state of mind, and with a personal instructor in control besides him.

These people sit in the car, think well about what they are going to do and what they really don't want to do. They set out and...do it. Or at least, they think they did. Recap: They were told to do (a) and not to do (b). They set out, thinking very well on doing (a) and not doing (b), set out, do (b) and think that they did (a). They spend some time argue with the instructors that they did (a), try again, and the same ordeal repeats itself two-three more times. Only after that, does the driver begin to apply corrective input with some efficiency.

Now, let's move fast-forward ten months. The driver has a new car with different handling characteristics, he is driving a wet, bumpy road at dark in a speed of 50mph, alone. The car breaks loose suddenly, would he be able to mimic his still crippled level of performance at the course a year-past?

To teach skid-control to a sufficient level of skill, it would take:

1. Knowing all of the basics of car control – understanding grip, car dynamics, drivetrains and engine layouts, being aware of changes in the coefficient of friction as road conditions vary, knowing how steer, where to look and how, etc. Trying to teach or even simply portray oversteer control in an article – when isolated from these other skills – is foolish at best.

2. Acquiring the aformentioned knowledge not through articles and not via trail and error, and not even in a Skidpan tuition. It takes a special, three-four day-long course for advanced driving and car control, or a dedicated skid-control tuition at the length of seven hours at least! In both cases, the instruction must be professional and based on practice on a special simulator (SkidCar device) and a follow-up drill performed in the driver's personal car, on dry and wet tarmac, and on tight gravel. Skidpan tuitions, where they use low-friction surfaces and inclines to induce the slide, are very ineffective.

Even with (1) and (2) done, the chance for a corrective input in real time to be effective rests between 30-40 precent, and a bad, inaccurate or untimed corrective input will make matters much worst than they would have been if the driver would let the car skid to a stop or brake to a halt.

For the car to suddenly “break away” and the driver recovering from it effectivelly, is none-existant. A driver that really knows how to recover from a skid, will either avoid it or know when it is going to occur, so it's not a surprise. He knows all of the variables that can change the corrective input required: Torque, grip, setup (front to rear grip levels), driveline (rear, front, etc), tranny, cause, existance of electronic controls, skill level and qualifications, speed, even the seat! If a driver reaches a situation where his car suddenly breaks away, he might manage to recover with luck, but he will never manage to perform an accurate, effective solution.

Unfortunately, skid control practice is difficult to come by - you certainly don't want to have to do it in everyday driving! Practice and experience it only in a safe environment.

One of the most common types of skids you may face is when the rear end slides out on you - the oversteer skid. What do you do? FIRST, STAY OFF THE BRAKES! If you touch them you will make matters worse. By braking, you transfer weight forward (the car nose-dives under braking) reducing rear tire traction and most likely causing the car to spin out completely. Instead, JUST LOOK AND STEER WHERE YOU WANT TO GO - this will automatically make you steer in the direction of the skid. In other words, in the direction the rear end is sliding (this is called "opposite lock"). And sometimes, very gently increase the throttle to cause a slight weight transfer to the rear, which increases the rear tire traction. I say sometimes because giving it more throttle may make things even worse. Think about it. What got you into the problem in the first place? Usually, too much speed. The last thing in the world you need now is more speed.

Completely wrong, and for various reasons. First, oversteer is the least common type of skid! ALL cars are set to do the opposite and UNDERSTEER, because oversteer is far too complex for the average road driver! Also, oversteer is not defined as “the rear end sliding on you”. Certain combinations of coarse handling and car setup can result in the car swaying laterally without breaking traction to the rear in particular. This would not be considered as oversteer! Oversteer is defined a rear slip angle larger than the front slip angle.

Second, while it is true that “touching” the brakes “make matters a lot worst”, The average road driver – including one who is a veteren of a single skidpad tuition – will do well by STAMPING on the brakes forcifully and than declutch while straightening the steering. Yes, this will shift weight to the front and off of the rear, but it will also result in two other effects. First, a dramatic lost of speed, and an exponential reduction of the Centripetal force and Angular Momentum that is sliding the car. Also, if the car stops, the skid stops and, if you do hit something, you are likely to just brush it at 8mph instead of crushing into it at 40mph.

Also, braking hard locks up all four wheels, at least momentarily. This makes them slide in the direction in which the moment of inertia is pushing the car. This, along with the reduction of speed, can straighten the car back up.

Furthermore, even when a driver is skilled enough to control oversteer, he should never do it in the prescribed method. It might sound great, but in reality it's much more complicated. Like I have said, there are no magic solutions for a situation like oversteer, and that includes “looking and steering”. What have you basically done by steering like this? Have you removed the cause of the skid? No!

Of course, the cause of the skid cannot be known before the author be kind enough to detail it, but I will tell you of two reasons:

1. In a powerfull rear-wheel drive car (and some four-wheel drive cars), when the driver over-powers the rear wheels with torque by giving it too much throttle.
2. In all drives, by suddenly throwing the car's weight forward by sudden braking or even an aggressive lift off of the throttle, mid corner. Both cases are different and require different inputs. The type of the drivetrain also carries great importance, as well as the existance of electronic software like traction control, the given amout of torque, the amount of grip, the speed, the angle of the skid, etc.

So, you probably understand by now that this is a complicated subject, much more complicated than this article presents it. That's the problem: Presenting a deep and complex subject with extreme simplicity, pretending to teach in writing what can only be taught via an intensive, orginised training program – all without even thinking about the wide audience of drivers (at different levels of skill or understanding of car control), the driving enviornments they deal with, and whether they did understand the article or not (which someone can make sure when he is instructing a student face to-face).

Still, for the sake of disscussion, I want to try and get you to understand the subject better. Of the two different inputs the author stated: The steering and the throttle, it would appear that steering takes priority and throttle is of a lesser importance or perhaps even optional. In reality, it goes the other way around.

If we get oversteer by too much torque applied on the rear wheels, we must reduce the amount of torque applied by...reducing the throttle input. However, usually we should avoid lifting-off completely to avoid a forward weight transfer. Also, with the case of oversteer caused by such a forward weight transfer, we would have to shift the weight forward...by accelerating!

That's what makes oversteer so catchy: Do you have the Huevos Grandes required to accelerate when the car attempts a spin at a high speed (or at least, avoid jerking off of the gas)? For the sake of dissscussion, let's say you did somehow get on the gas, do you have the skill and knowledge to judge the right amount of throttle, plus the nessecary steering correction, in just the right moment?

Remember, the throttle can overpower the driven rear wheels. Even in a front-wheel drive car, the increase of speed might make matters worst (like the author stated), especially when the driver applies too much, too late or does not make any steering correction while operating the throttle. It can also make the front lose grip and get the whole car sliding away from you.

In another article on this subject, referring to the differences between the driveline configuration and it's effect on driving style, Bentley said:

"You often hear people give the advice “accelerate hard in a turn with a front-wheel-drive car to ‘pull’ you out of a skid or slide”. Think about it. If the front tires are at or near their limit of traction, and you accelerate hard, all you are going to do is increase the understeer. Again, the tires have a limit. Respect that limit.” (Ross Bentley, “Different cars, Different techniques?”)

This conclusion of Bentley is right when referring to understeer. However, regarding oversteer, he is plain out wrong! Yes, the front wheels have a limit, so you increase it by taking the steering input out (straightening the wheel) and accelerate with feel. Also, even if the tires do spin somewhat, since the accelerator is usually the weakest car control, you are able to spin the front wheels but still get the weight transferred to the rear. This is GOOD, because the spinning front wheels get pushed away and straighten the car back up.

However, remember, even one hand on the wheel has more control than two feet would have, and two hands on one steering wheel have tenfold the control and authority than one foot (right foot) operating two pedals (throttle and brakes). A throttle correction is complex!

However, a steering-alone correction, as suggested by the author, is much worst. Run the scene at 100mph. How much steering would the driver have to apply and how quickely, to get the car under his control, and how quickely would he have to remove that input to avoid being thrown the other way? Furthermore, there is a difference between “catching” the slide and “recovering” from it. By steering the car, you try to keep the front wheels rolling naturally while making the turning radius wider.

When applied with skill, this can be enough to stop the car from spinning, but not from sliding. The driver will find himself obligated to turn the wheel more and more until he reaches full opposite lock, and than wait for the car to wipe off speed, hoping it would run out of speed before it runs out of road, which sadly tends to occur earlier. Than, the side-swipe would spin the car around only to suffer a second blow from the rail.

Furthermore, turning the wheel reduces overall traction and can make the situation worst by generating drag that shifts more weight to the front, or by reducing the amount of the traction that can be used to accelerate the car and pull it from the oversteer.

I understand from where the author concluded this manner of response to be right. If you drive on good grippy tarmac, at moderate speed, in a weak Rear-Wheel Drive car without a particularly light back-end, power oversteer and oversteer caused by braking in a bend, can be resolved in a sufficient manner by simply letting go of the pedals and steering: “If in doubt, both feet out”. However, take most cars in most conditions, and this correction is less effective, particularly if you dial in normal driver's response times. Even with cars where it might be tolerated, it's dangerous to categorily instruct this manner of recovery because you inherit bad habits that you will later apply in the wrong car/situation.

Once you catch the first slide or skid, be ready for one in the opposite direction caused by over-correcting. If it happens, gently correct for it by looking where you want to go and smoothly try to ease the speed down until you get the car under control again.

As the author described it: Steering where you want to go and than perhaps adding some throttle, what will happen is that the driver will compensate with a certain amount of countersteering, and as he accelerates, the car would suddenly re-grip with the front wheels turned against the corner.

This results in a pendulum effect that makes the moment of inertia toss the whole car ever more violently to the other way, and an increase of speed with the throttle only makes it worst. Besides being physically more severe, the pendulum skid is harder to recover from, because it's sharper and the driver has to remove the steering input and start steering sharply towards the other way in a rush. Also, with the origina slide, the car spins but often stops relatively close to where it started. With the pendulum skid, the whole car (not just the tail this time!) is immediately pointed towards the outside of the corner, leading to a roll-over off of the road or a head-on collision with a car in the opposite lane.

If you experience an understeer skid, with the front end sliding or plowing towards the outside of the turn, the correction is simple. Just ease off the throttle, which transfers more weight onto the front tires giving them more traction, AND STRAIGHTEN THE STEERING OUT SLIGHTLY. Most peoples' first reaction when faced with this type of skid is to turn the steering wheel more and more. But, this increases the problem because the tires were never designed to attack the road at an extreme angle. Tires were meant to face the road with their full profile, not with the sidewall, so their traction limit has actually been decreased. So, decrease the steering input slightly and ease off the throttle gently to allow the front tires to regain their grip, and then begin to steer again.

This paragraph is better but it stands in contradiction to the former. The author says not to “force” the car with the steering when experiencing understeer, so why does he recommend just that during oversteer? It's just the same: You try to “force” the car with the steering, but it does not respond, and you simply keep on putting more and more steering, run out of steering and than it's a question of what you run out of first: The speed or the road...

However, since understeer is recovered from by decelerating, steering more to make the car slide MORE and decelerate more, can sometimes be quite effective. This is why understeer is the preferred situation for the unskilled – it solves itself, and is tolerant to steering-based corrections.

Certain car designs lead to certain handling, and therefore skidding, characteristics. Most cars with a large percentage of the weight over the front wheels (front-wheel-drive cars or rear-wheel-drive cars with heavy engines mounted up front) tend to understeer at the limit. Cars with a large percentage of weight biased towards the rear (mostly mid-and rear-engine cars) tend to oversteer naturally. This is mostly caused by a pendulum effect the weight has on the heavy end of the car. If you quickly try to change direction (as in turning into a corner) in a naturally understeering car, the weight of the front end wants to keep going in a straight line causing the car to plow. In a mid- or rear-engine car, if you lift off the throttle in the middle of a corner (causing weight to transfer off the rear tires, reducing traction and making the car oversteer), the weight of the engine works like a pendulum swinging out and trying to spin the car (“trailing throttle oversteer”).

NO road or race car oversteers naturally. Only few car used in rallycrossing and drifting have natural oversteer and very few rally cars have neutral handling. Otherwise, any car would have some degrees of understeer. Drive it on a plain road of tarmac, maintain a constant speed with throttle and turn the wheel without any Appel Contre-Appel provocation, will it spin? No. So it does not naturally oversteer. Even if you try to turn the wheel more ubruptly, you are likely to aggrevate the understeer or cause the car to “cynical-steer”, it feels like oversteer but it isn't.

As you can see, weight transfer has a great influence on how your car behaves in a skid or slide. Smoothly controlling that weight transfer is the real key to skid control.

If the car begins to oversteer skid and you can't control it as described above, you are going to spin-out. Nothing wrong with that, if you keep your cool, watch where you are going, de-clutch and lock up the brakes - and hopefully don't hit anything. Remember these words, “spin – both feet in”, meaning left foot on the clutch and right foot on the brakes. That is all you can do - besides avoiding the spin in the first place.

Correction: The clutch goes AFTER the brakes, so you have some support with your left foot as you right foot stamps on the brakes. Unless the driver is very skilled, this is the sole manner of performing a sudden stop (no attempt of threshold braking) and the only way to recover from oversteer (no attempt to correct it).

Ross Bentley, Senior Instructor, Driving Unlimited

Professional Race Driver

“But it's Ross Bentley, surely he cannot be wrong?” Well, it's either him or: Chris Harris, Martin Rowe, Tim Harwey, Tiff Needell, Jason Plato, Tommy Makinen, Danny Glatter, O'n Ya'akobson, Lior Levi, Itay Alon, Colin Mc'Rae, and many others. Either they are all wrong, or Ross Bentley is right. I doubt it.