Precision ball bearings are manufactured to standards established by the Annular Bearing Engineers Committee (ABEC) of the American Bearing Manufacturers Association (ABMA). These standards have been accepted by the American National Standards Institute (ANSI) and conform essentially to the standards set by the International Standards Organization (ISO).
The ABEC and ISO bearing standards are primarily concerned with bearing tolerances. While tolerance is an important factor in the performance of a bearing, there are many other factors that also affect the suitability of a bearing to its application.
ABEC and ISO standards do not cover: radial play, raceway curvature, surface finish, material, ball complement, number, size or precision level, retainer type, lubrication, torque, cleanliness at assembly, packaging and other factors that may be essential to the desired bearing performance.