Bearing Tolerances and Precision Levels | AST BearingsABMA standard 20 defines 5 classes: ABEC 1, ABEC 3, ABEC 5, ABEC 7, and ABEC 9. Instrument series ball bearings are defined in standards 12.1 and 12.2 ABEC scale - WikipediaThe ABEC scale is an industry accepted standard for the tolerances of a ball bearing.  Bearings not conforming to at least ABEC 1 cannot be classified as precision bearings as their tolerances are too loose. The scale also works as a guide 
Abec vs. Skate Rated™ - Support - Bones BearingsThe answer is that "Bones Bearings are Skate Rated™ not ABEC rated." Bones®  The ABEC rating system includes grades 1,3,5,7, and 9. The higher the Ball Bearings ABEC Standard Tolerances Data - EngineersA ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.  The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.  The ABEC scale is an industry accepted standard for the Levels of Precision - Choose Wisely: How Fast Your BearingsAug 24, 2015 - ABEC includes five tolerances classes: 1, 3, 5, 7, and 9 with 1 being the widest and 9 the tightest. Thus, bearings with a higher ABEC rating What Are ABEC Ratings? | AST BearingsThere are five classes, going from widest tolerances to tightest: 1, 3, 5, 7, and 9. Higher ABEC classes provide better precision, efficiency, and greater speed