The essential drivetrain upgrade for outboard bottom brackets. Replace your existing BB bearings with performance Enduro bearings for increased efficency and extended bearing life. The entry standard for Enduro bearings. Enduro's ABEC 3 bearings offer improved quality and performance over ABEC 1 bearings fitted by many OE manufacturers. Only the finest cycling components come standard with Enduro's ABEC 3 bearings. With hardened chromium steel races, balls, and tough riveted steel retainers, these bearings are durable and the perfect low cost performance upgrade.