HEADSET The bearing unit that attaches the forks to a frame and allows them to turn. There are two varieties: threaded and threadless.
HEAD TUBE The frame tube through which the steerer tube runs.
HEXAGONAL BOLT OR NUT A threaded bolt with a hexagonal-shaped head, or a hexagonal-shaped nut that fits on to a threaded bolt.
HYDRAULIC A mechanical system that uses compressed fluid to move an object.
LOCKRING/LOCKNUT A ring or nut used to tighten on to a threaded object and lock it in place.
MECH Short for mechanism. Device that pushes the chain on to a larger or smaller chainring or sprocket. See also Derailleur gears.
NEGATIVE SPRING A device that works against the main spring in a suspension system. In compression, for example, a negative spring works to extend the fork, helping to overcome the effects of stiction.
NIPPLE The piece of metal attached to the end of a cable that secures the cable in the control lever.
PLAY A term to describe any looseness in mechanical parts.
QUICK-RELEASE MECHANISM A lever connected to a skewer that locks or releases a component from the frame.
REBOUND A term to describe the action of a suspension system after it absorbs an impact from the terrain. It refers to the extension of the system’s spring.