The entry standard for enduro bearings enduro39s 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 enduro39s 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 bearing code mr 21531 dimensions 215 x 31 x 7mm abec 3 grade 10 seals 2rs grease