Originally Posted by
badamsjr
Hillrider: You may be right about the ABEC numbering system. I just checked Enduro's site, and they show what I was calling ABEC3 as a "ZERO" bearing. What I was actually referring to is the ball grade: Grade 5 are 5/1000000"from being perfectly spherical. Grade 3 are 3/1000000" from it. The 'ZERO' bearing is then almost twice as smooth.
Right, loose ball bearings get better and more precise as the Grade number goes down. They are not the same as ABEC numbers.