Here we have a Shimano BB-UN52, 68mm Shell Bottom Bracket with 111mm Square Taper Axle. The bottom bracket feels fine, not perfect as it’s used, but doesn’t feel gritty and turns fine.
Shimano UN55 68mm Shell English Thread Sealed Cartridge Taper Bottom Bracket
Shimano BB-ES300 Octalink Bottom Bracket - 68mm
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Shimano Ultegra HollowTech II Bottom Bracket - BB-R60 - 68mm English
Shimano Tiagra BB-RS500 / 1 Hollowtech Road Bottom Bracket - BSA, 68mm
