What is the difference between this Shimano BB-UN50 and the BB-UN55 ? The former is hard to find for sale, the latter seems to be found everywhere : r/bikewrench
Shimano UN55 Square Taper Bottom Bracket 68X113 English I Nyc Bicyle Shop
Atelier Olympia - Shimano BB-UN54 Bottom Bracket - Atelier Olym...