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Bicycle Glossary - N


Needle bearing - A variation of a roller bearing in which the rollers are very thin in comparison to their length.  Needle bearings are lightweight, and good for handling radial stresses, but are weak with linear stresses.  Needle bearings are seldom seen in bicycle components.

See also: Ball bearings.

Nexus - A series of components made by Shimano. The most remarkable of these are roller brakes for front and rear hubs, and rear hubs with planetary gear sets that have 4, 7 or 8 speeds.

See also: Planetary Gearing, Rohloff

Non-friction bearing - Bearings are devices to allow parts to move against each other without wearing out, and without wasting energy. Bearings are made in two styles.  Friction bearings are simple, depending on lubrication or smooth materials to simply rub against each other.  Most derailleur pulleys use friction bearings. Non-friction bearings use balls or rollers (often called ball bearings), so that all movement involves rolling contact, so that nothing rubs.  Non-friction bearings are usually superior, but more costly, weigh a bit more, and do not work well in some unusual applications.

Non-turn washer - A specialized washer found on the axles of hubs with planetary gear sets which help prevent the axle from turning within the dropouts.

Numbness in fingers - See Carpal Tunnel Syndrome

Nut - A fastening device used with bolts, generally made of steel. A nut is a threaded ring, usually with six flat sides that can be turned with a wrench.


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Although I have attempted to cover the major safety issues, I cannot be responsible for your use of this information. Working on bicycles is dangerous if you do it without considering consequences of bolts left loose, known problems which are ignored, things which should be replaced but are glued instead, and so on. Proceed carefully at your own risk and use common sense. Jeff Napier, and all agents associated with this information, do not offer any guarantee or warranty for your use of this information.


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