Not having the same center.

Contrast with Concentric.

The degree to which stress-induced material deformation reverses in that material after the stress is removed. A "perfectly elastic" material completely returns to its original dimensions after stress is released.

The maximum stress which a material can sustain before permanent deformation takes place.

The movement of the lubricant between two moving surfaces.

When two tight-fitting moving surfaces have a lubricant introduced between them, the pressure of the lubricant rises. That higher pressure greatly increases the lubricant's relative viscosity, moving it into more equal distribution and film thickness across the surfaces.

The process by which a material loses strength and/or ductility. There are thousands of types and causes of embrittlement.

Corrosion which progresses laterally and parallel to the surface, generally at grain boundaries. The corrosion products which form work to force metal away from the body of the material, giving it a layered appearance.

Bearings that are narrower and/or have smaller outside diameters than standard or light series bearings of the same bore sizes.

Extra light series bearings are generally used to allow large shafts to fit small housings or small housings to hold large shafts. This is possible only when the loading is not severe.