The Shimano UN-55 Bottom Bracket at J&R Bicycles is a high-quality sealed cartridge bottom bracket featuring a durable aluminum alloy non-drive side cup. As far as ENG-threaded BBs go, Shimanos square-taper bottom brackets are the unofficial standard and offer unmatched reliability and performance. This BB will fit JIS square-tapered cranksets.

Specifications:

• MODEL NO: BB-UN55
• SERIES: SHIMANO