The Friction Circle - What Winning Drivers Know

The contact patch, is the area of your tires whichyou want. Accelerating down the straight you can
touch the road surface. This small area gives youspend it all with no problems. In the same way
friction or grip on the road. The next step inyou can brake with 1G. You can also corner left
understanding how to go fast is the Friction Circle.or right with 1 G maximum. Now assume you are
I'm going to try and describe this concept withoutcoming off of a straight with hard braking, if you
any drawings, so please bear with me. Thestart to turn into a corner, will you make it or
Friction Circle or Traction Circle is the idea thatslide off the track?
the total grip of your tires can be spent inThe answer is if you are braking at the maximum
acceleration, braking or cornering, or a combination1 G you have no grip left to turn in. You must
of these.relax the braking and the amount under the 1 G is
The idea is used by race car driving schools toavailable for cornering. In the same fashion if you
help you visualize what is happening to your tiresare going around a corner and approaching the
as you try and go as fast as possible around aexit and you need to accelerate the same
track.problem comes up. If you are using all of the tire's
Let's imagine that you have a car that will grip thefriction holding you on the track in the corner then
road with a 1 G tire. Visualize that your car inyou have nothing left to accelerate with.
sitting in the center of a circle. An arrow pointingRacing drivers overlap the different phases of
North represents the maximum braking possiblebraking, turning and applying power to try and
or 1 G. The arrow pointing South represents themake the tire work as hard as possible for as
maximum acceleration your tire can providelong as possible. It's the skillful use of this overlap,
without breaking loose or again 1 G. East andreleasing the brakes and feeding in the throttle to
West are arrows representing the maximumjust the right degree not to overwhelm the
cornering force of 1 G before you again breakavailable grip, which makes the best use of the
away. You can point your car in any direction on"traction circle".
the circle.The winning driver approaches the limits closer,
The idea here is that you have 1 G of Frictionthan the other drivers, without exceeding them
under your control, and you can spend it any wayand losing control of their car.