False brinelling

[4] Lubricant is pushed out of a loaded region during small oscillatory movements and vibration where the bearings surfaces repeatedly do not move very far.

In normal operation, a rolling-element bearing has the rollers and races separated by a thin layer of lubricant such as grease or oil.

Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress.

A major maintenance problem are the pitch bearings in wind turbines, for which specialty greases had to be developed that result in almost no false brinelling damage.

[19][20] Similar damage may also occur in electric and electronic contacts that are subjected to vibrations during use, think of aerospace and automotive connectors and even remote control battery compartments.

Until recently, bicycle headsets tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork.

Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement.