Braking force/tire slip

Curve I in the above chart shows the braking force as a function of slip.

Vertical axis: Braking force

Horizontal axis: Slip

The braking force is equivalent to the coefficient of adhesion or the friction between the tire and the road surface. Each application of braking force gives rise to a certain degree of slip. The slip of a freely rotating wheel is expressed as nil (0%) and of a locked wheel as 100%.

When the brake is first applied at zero slip, braking force increases sharply but the degree of slip increases only gradually up to a certain limit. Beyond that point, braking force decreases with increasing slip.

1. Lateral force
2. Stable braking zone
3. Unstable braking zone
4. Slip