Definition
The hardened steel ring of a ball or roller bearing against which the rolling elements (balls or rollers) ride. A bearing assembly typically has two races: an inner race that fits on the shaft and an outer race that fits inside the housing. The rolling elements run in a smooth track machined into each race.
Plain English
The smooth, hardened metal ring inside a bearing that the balls or rollers roll along. There is usually one ring on the inside and one on the outside, and the balls run between them.
Context Anchor
Seen in aircraft maintenance discussions about wheel bearings, engine parts, pulleys, and other rotating parts.
Derivation
‘Race’ here comes from an older mechanical use of the word meaning a channel or track that something runs along — the same sense as a ‘mill race’ where water runs. The balls literally race around in their track.
Why Pilots Care
Worn or damaged races cause vibration, heat, and eventual failure of rotating components, directly affecting flight safety.
Intuition Check
Do not read race here as a competition. In a bearing, the race is the track that the rolling parts move along.
Example Sentence 1
During the wheel bearing inspection, the mechanic found pitting on the outer bearing race and replaced the entire bearing.
Example Sentence 2
A scored bearing race in the nosewheel assembly produced a noticeable shimmy on landing.