A good quality bottom bracket for Shimano cranksets with sealed bearings for smooth movement and improved strength. The BB-UN55 is a durable, hard-wearing sealed cartridge bottom bracket with square tapered spindle fitting.
Lightweight hollow spindle
Maintenance-free sealed cartridge bearing assembly keeps out dirt, mud, and water for long bearing life
Fast and easy installation without adjustment
Narrow body allows clearance for cable routing under the bottom bracket