For full details on bearing grade, please see our Skate Bearing Buying Guide
Bearings are an essential part of an inline skate. Bearings determine the smoothness of your ride and also determine your ability to reach higher speeds .The idea behind an inline skate bearing is to reduce the friction that exists between a moving skate wheel and fixed, non-moving frame.
ABEC: Most bearings on the market today use the ABEC system, which is a standardized system that was designed originally for bearings that are used in machinery. The ABEC scale runs from 1-9, the higher the bearing number the better the precision. Other factors need to be accounted for, such as you can’t put an ABEC 9 in a 72mm wheel and expect blazing speed. If you are going with an ABEC 9 bearing you are going to want to pair it in a wheel with a size of 90mm so you get maximum performance.
ILQ and SG: A system that was designed specifically for K2 and Rollerblade brand skates is the ILQ and SG ratings; these systems use the same number scale as the ABEC system with the higher number being the more precise bearing.