This extremely slow rotation is desirable as it prevents repeated stressing of the same portion of the stationary race. Wear resulting from the proper creep is negligible and no damaging abrasion occurs. However, abrasion caused by locked bearings or the improper fit of the races must be prevented. Cracked races will usually be recognized by a definite thump or clicking noise in the bearing during operation. Cleaning and inspection is the best means of determining if cracks exist.
Cracks usually form parallel to the axis of the race.
The cracking of bearing races seldom occurs if proper installation and removal procedures are followed. Excessive looseness may occur on rare occasions even though no surface disintegration is apparent. Since many frictionless bearings appear to be loose, even when new, looseness is not always a sign of wear. The best check for excessive looseness is to compare the suspected bearing with a new one. Wear of bearings, which cause looseness without apparent surface disintegration, is generally caused by the presence of fine abrasives in the lubricant.