In competitive driving, traction is the key to everything. The available grip determines your acceleration, your braking and your ability to turn. In other words, everything that allows you to go fast.
Drive Like a Pro is a series that will show you how to use the skills and knowledge acquired by our rally drivers to drive more safely and effectively on the road.
How often do you think about your car’s tyres and the hard work they do? Chances are, not often enough. So, let’s start now. Just imagine the tyre’s contact patch – an area about the size of the palm of your hand which is the only thing connecting your car and the road. One or two tonnes of speeding metal, stabilised, accelerated, braked and steered by just four palms’ worth of rubber.
It is fascinating that something so small can tame such forces. The miraculous abilities of a modern car’s tyres and suspension are not, however, what we want to talk about. Today, we want to remind you of the fact that the amount of grip and traction you have is finite – and that everything you do takes from the same “pool”.
This means you can use your grip either for accelerating, for braking or for turning. Whatever you use for one kind of manoeuvre, is unavailable for another. If you are braking or accelerating at the threshold of your grip, you don’t have anything left for turning. And vice versa – if you are at the limit of your grip in a turn, you cannot brake or accelerate, in case you lose your grip and go into a skid.
To make it easier to understand, let’s use the “circle of traction” you can see in our infographic. On the vertical axis, you have either accelerating (up) or braking (down). On the horizontal axis, you have turning to the left or right. The circle represents the limit of your grip. Venture outside, and you’re sliding away from your chosen line.
If you keep this picture in mind, you will always remember that while you certainly canturn and brake, or turn and accelerate at the same time, you cannot do it with the same efficiency as when you are doing just one thing. You always have to think about dividing the grip you have available between the manoeuvres you need to perform.
Of course, this graph is extremely simplified – in real life, it will never be a symmetric circle. Instead, it will probably look like a deformed ellipse or some even more complicated shape, depending on the properties of your tyres and suspension, your car’s weight balance and other factors – but this is a great way to visualise the basic idea behind grip.
In the next instalment, we will look at oversteer, understeer and how to avoid them – or use them to your advantage!