5- Cornering

WEIGHT TRANSFER TECHNIQUES

The trick to driving fast in circuit racing and on winding roads is cornering.  (For straight ways. all you need is to go full throttle in the correct gear.) This section discusses the quickest ways to enter and exit a corner connecting two straight ways.

To corner as fast as possible, you must use weight transfer techniques while using 100% of the tires' traction.

ENTERING A CORNER

As you turn the steering wheel to enter a corner from a straightaway, the fastest way to enter the corner is to use the maximum traction available from the front tires. To raise the traction capacity of the front tires, use the brake to shift the weight of the car forward. As you turn the steering wheel to enter a corner, apply the brakes lightly. If you stop braking before you turn the steering wheel, all the weight that had shifted forward during braking will shift to the rear again, thus reducing the traction of the front tires. It will take practice to get a feel for braking just the right amount.

When cornering, apply the brake while turning the steering wheel.

As was explained earlier using the friction circle, if you apply the brake too hard, all of the front tires' traction will be used to stop the car, leaving no traction for turning the car. You should use 100% of the tires' braking ability in the straightaway before the corner to slow the car down, and right at the end, with the brake still lightly pressed, you should begin to turn the steering wheel. This maneuver will take time to learn. To repeat, you must not suddenly release the brake as you enter a turn, but instead you must apply light pressure to the brake pedal. If slamming the brakes were rated a 10, then the amount of pressure you need to apply during a turn is about a 3 or 4 (although this will depend on the situation). By keeping the brake lightly applied during a turn, the weight of the car remains shifted forward, which results in better front tire grip and hence an easier turn. Only after the car has turned sufficiently should you begin to release the brake and then accelerate to exit the corner If as you enter a turn you immediately spin out, this is due to either too much weight being shifted to the front or the car is traveling too fast. If there is too much weight transfer to the front, you must release the brake a bit sooner. If the car's speed is too fast, then you must begin applying the brake a bit sooner before entering the turn.

EXITING A CORNER

Once you enter a corner properly, the next step Is to prepare to accelerate out of the turn into the straightaway. The trick here is how early you are able to begin accelerating. However, it isn't just a question of randomly going full throttle. You must employ weight transfer techniques to use 100% of your tires' traction capacity. By entering a corner and turning, you destabilize the car. Another way of looking at it is that you are purposely creating a situation where the car is susceptible to spinning out. If you were to continue to keep the steering wheel turned, the car would most likely spin out. Right before the car begins to spin out, you want to stabilize the car and accelerate out of the corner.

The point where you would like to start accelerating is right about at the apex of the corner (explained in "Cornering Line" beginning on pg. 18) or just a little before it. The apex will depend on factors such as the size of the corner, as you'll read in the explanation. So how do you stabilize a car that is just about to go into a spin? Since a spin occurs when the lateral force acting on the rear tires exceeds its traction capacity, you must increase the grip of the rear tires. This can be done by accelerating and shifting weight to the rear of the car. In other words, by stepping on the gas you can stabilize the car. The difficult thing Is knowing exactly how much to accelerate. This will depend on whether the car is rear-wheel or front-wheel drive. For rear-wheel drive, if you accelerate too much, the traction demanded in the straight-line direction on the rear tires will increase, resulting in the sum of the straight-line and lateral components exceeding 100% of the friction circle limit. This will cause the rear tires to slip and the car will instantly go into a spin. This maneuver requires getting a feel for how much weight is being shifted to the rear without overloading the rear tires' traction capacity. The best way to approach this is to accelerate lightly to shift the car's weight to the rear to stabilize the car, then gradually open the throttle to exit the corner as fast as possible.

Another mistake that beginners make is to accelerate too much without turning sufficiently, thus causing understeer and increasing the path the car takes through the corner. By not turning sufficiently, you will not destabilize the car enough, thus leaving plenty of traction available for the rear tires. By accelerating at this time, you transmit the available traction in the straight-line direction. The car is able to accelerate quickly, shifting the weight to the rear, causing the front tires to lose their grip. Thus even though the steering wheel may be turned correctly, there is not enough traction on the front tires to turn properly, leading to understeer, If this occurs, you must increase the time you have the steering wheel turned while applying the brake. If this doesn't work. this means that the entry speed into the corner is too slow. Increasing speed should make it easier to turn.

With front-wheel drive, even if you accelerate suddenly the car will not spin out. Because the increase in power will only lead to a loss of traction in the front tires, at worst this will only cause understeer. Therefore the most important factor for being able to exit a corner quickly with front-wheel drive Is how to avoid understeer and open the throttle as much as possible. The technique for turning into a corner and destabilizing a car is the same for front wheel drive as rear-wheel drive. Lightly accelerating the car will re-stabilize the car. By returning the steering wheel to center in accordance with the degree of curve in the corner, you will slowly reduce the amount of lateral traction used in the front tires and continue to Increase its straight line traction. In both front-wheel and rear-wheel drive, you will get 100% traction performance by always keeping in mind the distribution of a tire's lateral and straight-line traction components. If you are using nearly 100% of a tire's traction capacity, any sudden acceleration/braking or wheel turn will easily result In exceeding the tires performance envelope.

When exiting a corner, the most important thing Is to shift the car's weight to the tires that will require the most traction.

CORNERING LINE

ROUNDING THE SIMPLE CORNER

The fundamental rule of cornering is said to be "out, in, out." This means to take as wide a turn as possible to cut down cornering time. A car should enter a corner from the far side of the lane, gradually edge towards the inside of the lane, and then exit the corner on the outside of the lane. The point at which the car comes closest to the Inside of the lane is known as the apex.

The apex must be as close as possible to the Inside lane of the corner. If you fall to fully reach the inside part of the lane, this will Increase the distance you must travel and slow down your cornering time. If you are trying to direct the car to the inside but the car won't respond, this is probably a case of understeer. Where should you try to apex when you enter a corner? The image you have in your head will determine the line you take. Ordinarily, the wider the turn you make in a corner, the higher the cornering speed you will attain. For a simple corner as in figure A, the ideal cornering line will be a perfect circle. This will provide the fastest cornering time A for the corner portion only.

However, if you take into consideration trying to achieve the fastest lap time in a circuit race, it is advantageous to have a higher exiting speed from the corner as you head into a straightaway. An example of an often used cornering line is shown in figure B. Although the illustration Is a bit exaggerated, the entry turn into the corner is taken slowly to create a very tight turn. This allows the final half of the corner to be taken with a wider turn, enabling earlier acceleration. Compared to a cornering line that is a perfect circle, the exiting speed is higher for figure B.

Figure B

Figure C

A common term used in race car driving to signify a high exiting speed is "slow in, fast out." The apex here is a bit further along the corner than for figure A, and is the most effective means of creating a wide exiting line.

CORNERING S TURNS

Emphasis on high exiting speeds pays dividends for S turns and multiple cornering. As shown in figure C, the unbroken line represents the line taken emphasizing a higher exiting speed, with each apex coming deeper into

each corner. The dotted line represents the line in which the corner is taken at a perfect circle. It is clear to see that the unbroken line would produce higher exiting speeds around each corner. It's important to always think ahead of the optimum cornering line to maximize the exiting speed for each corner. It is desirable to enter the second turn of a multiple-corner turn from the outside of the lane. To accomplish this, the first corner must be taken with a sharp turn, otherwise the car will drift to the outside. It is also important not to gather too much speed around the first corner, to enable the car to remain on the furthest left-hand side of the lane as it enters the second corner.

Always plan on how you will set yourself up for the following corner.