A brake hydraulic cylinder in a drum brake. It is fitted to the back plate on the wheel axle assembly.

The centre assembly of a wheel containing the wheel bearings.

Connects the rim to the wheel hub.

The distance from the wheel nave to the centre line of the wheel. Used to accommodate the brake assembly and bring the centre line of the wheel into close alignment with the centre line of the steering swivel and wheel hub.

The plane (flat area) through the wheel at right angles to the axle.

Part of wheel that holds the tyre.

Loss of friction between a tyre and the road surface allowing the wheel to spin faster than the speed of the vehicle.

The dimension between the centres of the road wheels on one axle. Also known as tread.

Loss of friction between a tyre and the road surface allowing the wheel to spin faster than the speed of the vehicle.

The throw out of a rotating shaft. In relation to drive shafts whip can create unpleasant harmonics and vibrations.