Off-Road Terms Glossary

RPM is short for Revolutions Per Minute.

The Race, or cup as it is also called, is a press-in hardened surface for a bearing to ride on.

Tires built with perpendicular plies across the crown of the tire, effectively strengthening the tread for street driving. These tires also require belt plies going circumferentially around the tire for solidarity purposes.

A ratio is a quantity that denotes the proportional amount of one quantity relative to another.

The reverse rotation gear set was developed for use in front axle applications. The standard gear, when used in a front application, is running in reverse. This means the coast side of the gear is being used as the drive side. The convex (Drive) side of the gear is capable of carrying more load than the concave (coast) side. On a reverse ring and pinion, this problem has been corrected to create a stronger axle assembly. This was also done to help with driveline angles and reduce vi

The distance between bead seat to bead seat at bead seat radius.

The measurement between the flanges of a rim.

The Ring Gear, also known as a Crown Gear, is the gear that is bolted to the carrier and driven by the pinion gear, thereby turning the carrier.

The Root, or Flank, of a gear tooth is the very bottom or base of the tooth that spans the gap between the teeth.

Referring to a brake rotor, this is the part that the brake caliper clamps down on to slow the vehicle.

Run out is an undesired movement of a part through its motion, or wobble.