SHIMANO UN55 BB Square Taper Bottom Bracket Review Posted by Pelicandy October 1, 2018 in Drivetrain Components Bottom Bracket Fit – 68mm BSA of ENG Sealed cartridge bearings The Shimano BB-UN54/55 Square Taper bicycle bottom bracket gives you reliable strength for square tapered cranksets. Random Products Monster Motion 86 Link #25 Chain for the Razor E20... SHIMANO XT 8000 5-Piece Groupset Without Crankset ... Campagnolo Centaur Triple Tapered Spindle Road Bic... Shimano Deore XT CS-M770 9-Speed Cassette – ... Cycling Outdoor Recreation Parts & Components SHIMANO Sports & Outdoors