Arm that works on a rocker shaft to open a valve on an overhead valve engine.

A shaft, usually at the top of an overhead valve engine, on which the rockers pivot.

A switch that has two or three positions. Often used with the centre as an off position and then with a voltage reversal process as it is rocked in either direction.

Vehicle body movement from side to side.

A type of bearing consisting of a series of parallel rollers held in a cage between inner and outer bearing tracks.

A type of fuel pump that uses a rotor and a series of parallel rollers in an elliptical casing to produce the pumping and carrying chambers of the pump. Usually electrically driven and used on many fuel injection systems.

A type of fuel pump that uses a rotor and a series of parallel rollers in an elliptical casing to produce the pumping and carrying chambers of the pump. Usually electrically driven and used on many fuel injection systems.

The frictional value for the circumferential surface of a rolling component in contact with the track or road on which it runs. An example is the rolling resistance of a road tyre on various road surfaces.

Rollers set into the ground on which the wheels of a vehicle can be run. The system can then be used to check performance under driving conditions.

Read Only Memory in a computer, which is the permanent memory that is retained even when the power is switched off.