Technical info - How ABS works

Technical info

How ABS works

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Can explain in general terms how ABS works - including its strengths and weaknesses.

Follow the numbers 1 - 8 to read how ABS works.

Main processes in antilock braking systems

Point '8' describes the pressure variation happening up to fifteen times per second. This will depend upon the quality and sophistication of the system. The more times per second the system operates the more time the tyre delivers threshold braking and some steering. Repetitions that are more frequent also result in a smoother operation. In less sophisticated systems the feedback to the driver can be quite alarming.

The diagram shows ABS applied to one wheel only. Not all ABS equipped vehicles have ABS on each wheel. The system may apply in various ways.

Four wheels independently (four channel system).

Two front wheel independently and the back wheels together (three channel system).

The rear wheels only. This applies to some trucks and utilities, particularly older ones. In these vehicles, if either rear wheel (or trailer wheel) locks, the ABS activates on the brakes of both wheels. Some early American ambulance chassis had this system. The ABS in these vehicles is next to useless. It is primarily designed for vehicles that sometimes carry heavy loads and lockup easily when unladen. There is no steering advantage.

Return to the relevant performance criterion							Can explain in general terms how ABS works - including its strengths and weaknesses.
Return to the relevant performance criterion
							Follow the numbers 1 - 8 to read how ABS works. Main processes in antilock braking systems Point '8' describes the pressure variation happening up to fifteen times per second. This will depend upon the quality and sophistication of the system. The more times per second the system operates the more time the tyre delivers threshold braking and some steering. Repetitions that are more frequent also result in a smoother operation. In less sophisticated systems the feedback to the driver can be quite alarming. The diagram shows ABS applied to one wheel only. Not all ABS equipped vehicles have ABS on each wheel. The system may apply in various ways. Four wheels independently (four channel system). Two front wheel independently and the back wheels together (three channel system). The rear wheels only. This applies to some trucks and utilities, particularly older ones. In these vehicles, if either rear wheel (or trailer wheel) locks, the ABS activates on the brakes of both wheels. Some early American ambulance chassis had this system. The ABS in these vehicles is next to useless. It is primarily designed for vehicles that sometimes carry heavy loads and lockup easily when unladen. There is no steering advantage.