BB-UN55 Bottom Bracket

Product Information

The Shimano BB-UN55 Bottom Bracket is a highly regarded component, known for its robust construction and dependable performance. Though now discontinued, it was long considered a benchmark for square taper bottom brackets, prized for its durability and smooth operation. Riders often preferred its aluminum non-drive side cup, which offered improved longevity and easier removal compared to plastic alternatives.

Features

• Sealed cartridge bearings for smooth and maintenance-free operation
• JIS square taper spindle interface for traditional cranksets
• Full metal body with an aluminum non-drive side cup for enhanced durability

Specs

• Shell Type: English (BSA) threaded, 1.37 x 24 TPI
• Shell Width: Commonly 68mm, also available in 73mm
• Spindle Type: JIS Square Taper
• Material: Steel spindle and bearings, aluminum non-drive side cup
• Weight: Approximately 286g (varies by spindle length)