Question: what are abec 9 bearings?
Answer: The 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. High precision and small tolerances are required for bearings to function at very high RPM, in products like high speed routers that must spin at 20 to 30,000 RPM.