Glossary

A glossary of bicycle and bicycle parts and their functions.

Schrader valve

A type of air fill valve used on automobile and bicycle tires. See presta valve

Seating

The way a tire is mounted on a rim. A properly seated tire will be nicely round producing a smooth ride. An improperly seated tire can have bulges of flat spots, and can even blow out if very poorly seated.

Sew-up tire

A tubular tire.

Skewer

The portion of a wheel quick-release mechanism that extends through the hub axle.

Snakebite flat

A flat tire caused by pinching the tire and tube between the rim sidewalls and a rock or other obstruction. It usually causes two parallel punctures in the tube that look like a snake bite.

Spoke fatigue

A condition in which spokes have reached their maximum life span. This is affected by the stressing and de-stressing that occurs with every revolution of the wheel. The metals of the spokes begin to develop stress fractures which eventually lead to failure of the spoke. This usually only becomes a problem with wheels that have been in use for a great number of miles.

Spoke key

A small wrench for adjusting spoke tension by turning the nipple. Also called a spoke wrench.

Spoke nipple

A long thin nut that fastens a spoke to the wheel rim. By turning the nipple, the spoke can be tightened or loosened, and by adjusting several spoke nipples, the wheel can be aligned.

Spoke nipple

A flanged nut that threads onto the end of a spoke attaching the spoke to the rim.

Spokes

Thin metal rods that hold wheels together. Spokes are used to attach the rim to the hub.

Suspension hub

A ruggedized hub designed to be used with a suspension, which induces more shock and work load to the hub.