Wheel Bearing

Wheel Bearing is a set of steel balls or rollers held together by a metal ring called a race. They help wheels spin fast with as little friction as possible. They are used on all kinds of vehicles, from bicycles to aircraft and cars. On a car, a wheel bearing rides on a metal axle shaft and fits tightly inside the hub, which is a hollow chunk of metal at the center of the wheel. The hub holds the lug bolts that you use to bolt the tire onto the wheel. The wheel bearing is pressed into the hub from the back.

Wheel bearings are becoming more and more unitized and easy to install, with the number of parts decreasing from the first-generation to the third-generation.

Usually we call the first-generation wheel bearing as wheel bearing or wheel hub bearing,and the send-generation and third-generation wheel bearing as wheel hub assembly or wheel hub unit.