Rotating the car for the best exit

‘Scrub comes out of the tyre, the bite level goes up and in turns the nose’

LAST MONTH WE TALKED ABOUT making the shortest possible corner. But to fully achieve this we need to quickly rotate the car to get the best possible exit.

As we enter the corner we decrease the brake pedal pressure, and that’s connected to the rate with which we turn the steering wheel towards our apex. Imagine a length of string tied to the steering wheel at one end and underneath your braking foot at the other: when you turn the steering wheel it pulls your foot off the pedal.

When we use the brakes hard – having first introduced them in a ‘soft’ way, of course ( evo 248) – we get an underrotation of the wheels compared to the speed of the car. This is roughly three to five per cent, so at 100mph we have around 97mph at the wheels.

We’re now into the corner, and having slightly turned the steering in a soft introduction ( evo 247), and started to reduce brake pressure (recall that piece of string), we’re near our point of car rotation, still with roughly three per cent under-rotation of the wheels – let’s say now 48.5mph compared to the car’s 50mph. That creates a bit of understeer, so we reduce the brake pressure just a fraction more and the wheels speed up, say to 49.5mph. With the car’s speed still dropping, at 45mph both wheel and car speeds are in sync, and the scrub comes out of the tyre, the bite level goes up enormously and in turns the nose.

Get it right and it’s a really short corner: you can help it with a little steering input, or in a rear-driven car perhaps ten per cent throttle to keep the back end moving.