Large End Wear
If the larger end of the roller shows smearing, spalling or galling, the bearing adjustment has been set too tight.

Spalling is when the surface breaks up into chips or fragments. Galling is when the surface is broken by friction or abrasion.

Roller End Wear
If the end of the roller is spalled, it means the roller has been running against the inner ring.

The inner ring has flanges on each edge to keep the rollers in line. If the bearing is overloaded (tightened too hard) during adjustment, the edges of the rollers will ride against the flange, producing the wear you see here.

Small End Wear
If you see wear, smearing or spalling, on the small end of the roller, it indicates that the bearing adjustment is too loose.

As you can see from this brief overview, correct bearing adjustment is a critical factor in bearing life. CR has worked with the Fleet Maintenance Council in establishing a standard practice. A copy of this standard is available here.

Worn race
When you inspect a bearing for damage, you must carefully inspect the inside surface of the cup (the race) for signs of wear.

When the race is worn, it indicates that the bearing may have been overloaded.