abec 9 Bearing

Abec 9 Skateboard Bearings | Lily BearingAbec-9 has been the highest grade in bearing industry. The Abec 9 rollerblade bearing can be applied to any harsh conditions with high speed requirementsABEC scale - WikipediaThere are five classes from largest to smallest tolerances: 1, 3, 5, 7, 9. The higher ABEC classes provide better precision, efficiency, and the possibility of greater 
The ABEC Myth | Transworld SKATEboardingJul 13, 2002 - The ABEC rating system uses odd numbers, ranging from 1 to 9. The higher the number, the tighter the tolerance of the bearing, and thus, the Abec vs. Skate Rated™ - Support - Bones BearingsThe ABEC rating system includes grades 1,3,5,7, and 9. The higher the ABEC rating, the tighter the tolerances are, making the bearing a more precision part