I've been amazed with these full ceramic BB's. my buddy is the techno-gee-whiz guy on the subject. From what I know, the ceramic balls + the ceramic races, are at least 5 times harder than the best steel bearings. Plus there is something going on with the retainers and seals, that have little to zero drag. the bearings are so crazy hard, that they grind up dirt. something like riding on diamonds.