LUCKY ABEC-7 Bearings : Skateboard  I wish I had more closely inspected these bearings before skating with them. As you can see in the photo, one of the four bearings was not produced properlyWhat 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 
The ABEC Myth | TransWorld SKATEboardingJul 13, 2002 - Most of what the skateboarding public knows about the ABEC rating of . between an ABEC 3 and an ABEC 7 bearing as subtle, and doesn't 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 ABEC scale - WikipediaThe ABEC scale is an industry accepted standard for the tolerances of a ball bearing.  Due to these factors, an ABEC 7 classified bearing could perform better than an ABEC 3 bearing. Bearings not conforming to at least ABEC 1 cannot be FREEDARE Bearings 608, ABEC 7 Bearings  Amazon.com : FREEDARE Bearings 608, ABEC 7 Bearings - Skateboard Bearings, Longboard Bearings, Skate Bearings（Blue, 1 Set of 8 : Sports & Outdoors