Threshold braking

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Threshold braking or limit braking is a driving technique most commonly used in motor racing, but also practised in road vehicles to slow a vehicle at the optimum rate using the brakes. This is mostly used in vehicles without an anti-lock braking system fitted, which automatically regulates brake pressure when locked wheels are detected.

The technique involves the driver controlling the brake pedal (or lever) pressure to maximise the braking force developed by the tires. The optimal amount of braking force is developed at the point when the wheel just begins to slip. Braking beyond this point causes the tire to slide and the friction adhesion between the tire and driving surface is reduced. The aim of threshold braking is to keep the amount of tire slip at the optimal amount, the value that produces the maximum frictional, and thus braking force.

When wheels are slipping significantly (kinetic friction), the amount of friction available for braking is typically substantially less than when the wheels are not slipping (static friction), thereby reducing the braking force. Peak friction occurs between the static and dynamic endpoints, and this is the point that threshold braking tries to maintain.

[edit] See also

• Cadence braking
• Anti-lock brakes
• Friction