A spring loaded valve for retaining the pressure in a tyre and to allow for tyre inflation. Fitted into the rim of a wheel either as a separate valve for tubeless tyres or as part of the tube for tubed tyres.

Neuralgia of the hip and thigh.

Short for oscilloscope - Test equipment with a screen that can display electrical signals.

Piston ring that controls amount of oil on cylinder wall.

A method of increasing force.

Effect on the tyre of steering turn.

A rubbing wear due to lack of lubrication or incorrect alignment. Examples are cylinder scoring and tyre tread wear on one side of a tyre only.

Oil, water or gas tight join.

The area on shafts that an oil seal lip seals against.

A liquid material that is used with or, in place of, a gasket to give a gas or liquid seal. Sealants can be either fully setting and go hard after application or non-setting which remain flexible in use. The correct type of sealant should be selected.