BB-UN55 vs BB-UN300 - which is the better square taper bottom bracket? - restoration.bike
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 Bottom Bracket
Shimano BB-UN55 Square taper Bottom Bracket 70 x 113mm