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 BB-UN55 bottom bracket British thread (68mm)
BB-UN55 vs BB-UN300; which is the better square taper bottom bracket? - YouTube
SHIMANO BOTTOM BRACKET UN-55 | eBay
Shimano BB-UN55 Square Tapered Bike Crank Bottom Bracket 68 x 122mm NEW!!! | Far West Product Sales
BB-UN55 vs BB-UN300 - which is the better square taper bottom bracket? - restoration.bike
Shimano BB-UN55 Bicycle Bike Square Bottom Bracket 107-127.5mm Sealed Cartridge Bearing - AliExpress Sports & Entertainment
Shimano Deore BB-UN55 68 мм X 110 мм Bottom Bracket Silver New | eBay
BB-UN55 vs BB-UN300 - which is the better square taper bottom bracket? - restoration.bike