No matter the machine, all cars have one common element. The only thing that is constantly touching the ground are its tires. Those rubber contact patches are crucial to what helps accelerate the car, slow it down and keep it attached to the ground. Managing the weight of the car between the limits of its four contact patches of the tires generates the speed and lap time we’re all looking for.
In its most basic principle, we as drivers are tire managers. Now that’s easy to talk about, but a lot more challenging to accomplish in the real world. So where do we get started? Let’s start first with understanding how a tire basically works.
For simplicity sake, think about a tire being able to do only three things – help the car (a)ccelerate, help the car (b)rake and help the car (c)orner. (ABC) A tire has a finite amount of grip and useable life available to keep the car on the road surface. As a car enters a corner, the driver balances the machine’s weight over its tires using the steering wheel, throttle and brakes. As he drives through the corner, he will place more emphasis over on one of the three tire dynamics more than the others. It’s all one big balancing act.
The key thing to remember is that using the tires is always an equivalent exchange, and the elements are always overlapping. The more of one dynamic you introduce, the less of the others that you have available. You have to give some input back, in order to use something else. Grip does not come for free.
But what does that mean? Let’s use an example.
Let’s pretend that you’re on a race track in a car moving down a 100 mph straight away, and about to enter a slow-speed 25mph corner. As you travel along through the corner, we’ll break the corner into phases and discuss how much you’ll manage the grip to get the most speed available.
Entering from the high-speed straight- Since you’re moving at 100mph, you’re going to have to apply the brakes hard to slow the car down. Ideally you’re using 100% of the tire’s gripping ability as you get on the brakes. This means that you cannot introduce any other inputs into the tire while you’re on the brakes. So you’re braking in a straight-line because you don’t have the grip for anything else. Easy, so far.
Turning into the corner- It’s great that you’re using 100% of the tire for braking, as you’re slowing down at the maximum possible rate. However, you still need to turn the upcoming corner! As you finish the braking phase and enter the corner, you’ll smoothly start to remove the braking pressure off the pedal. As you release pressure on the pedal, you’ll be using less of the tire’s available grip for braking. You’re not going that fast, (remember this is only at 25 mph), but you still want to use the entire potential of the tire.
This means now you’ll have some tire grip ‘in the bank’ to turn the steering wheel into the corner. As you turn the wheel in, you now have some grip to get the car rotated. At this point, let’s just say that you’re using 50% of the tire to brake, and 50% for cornering.
You haven’t even touched the throttle yet. You don’t have the tire grip available for it.
Mid Corner and Apex- The car is now turning into the corner, so you’re off the brakes now. The weight of the car is leaning on the outside tires, asking more grip from them. Let’s say that you’re using 90% of the tires grip for cornering. You’ve turned in for your apex and for the first time, you’re going to be using the throttle, as you need to keep the car balanced in the corner and eventually moving out of it. So you gently and smoothly apply the throttle.
However, because you’ve already turned in so much, you effectively can only use 10% of the throttle until you’re facing more straight. It’s a bummer, but you have to wait until you move through more of the corner.
Corner Exit- Almost done! Now you’ve gotten the car to the apex, and now you need to get the car straightened up, so you can go into the next straight away. Smoothly unwinding the wheel so that you’re cornering less, and you can start accelerating more. The straighter the wheel becomes, the more throttle you can use. So when you’re fully straight, the car is at full 100% throttle, rocketing out of this corner and into the next one!
That may have seemed like a lot, but in real world terms the entire corner may have taken two or three seconds to drive through. As you are driving, you need to remain aware how much available grip you have at all times, and how to best utilize it throughout every corner on the track.
As a tire manager, the objective is to be able to use as close to 100% of the tire’s potential at all times, while not overloading it. Overloading the tires makes it take longer to respond, extending your braking distances and makes it harder to control the car until it slows down to rotating to the proper speed.
Keep in mind that the more stress one puts on the tire, the sooner it will wear out. If the tire is constantly experiencing excess stress due to rough inputs by the driver, excessive heat builds up and the traction capability of the tire reduces over time. Experiencing moments of understeer or oversteer are caused by the grip limit of the tire being exceeded at the front or rear respectively. This slows the car down through wheel spin as the tire slows to the appropriate speed in order to reduce lateral sliding and ultimately regain grip.
Let’s take a look of a good example of a driver who has good tire optimization skills. Below is a video of Jenson Button in 2004, doing a qualifying lap in Imola. Observe the smoothness of his steering inputs as he turns into the corner and straightens the wheel at the apex. Listen to the smooth application of his throttle as he comes on and off the power.
As you become a more advanced tire manager, you will learn how to adapt your driving style to how the tire is reacting underneath you. It’s all about understanding the balances that you have to make in your driving style in order to use as close to one-hundred percent of the tire’s potential as you can lap after lap.
We’ll talk about more how to change your driving style to get the most out of a tire in a future artcle. For now, just think about the ABCs of tire management, and let me know what you think.