Bottom Brackets

Shimano's BB-UN55 Square Spindle Bottom Brackets are the unofficial standard for English-threaded cartridge bottom brackets. Quality, value, and durability come together to keep you cranking for many, many miles. - Fits JIS Square-Taper Cranksets - Hollow spindle - Crankarm fixing bolts not included

Shimano's Ultegra bottom bracket uses Pro Tour-proven technology for lighter weight and super smooth spinning, while still maintaining the same level of durability and stiffness. It's available in English, Italian, or Press Fit models.

• Lightweight seal structure removes grams • Durable anodized finish • Includes left and right hand cups, spacers, inner cover, and inner o-rings • Easy installation with TL-FC25 tool • Compatible with 24mm crank spindles • English, threaded: 68/73mm bottom bracket • Pressfit: BB86/92 bottom brackets

Pressfit Model: • For use on BB86/92 bottom bracket shells • Compatible with 24mm spindle Hollowtech II cranksets • BB Shell Width (mm): 92 mm • BB/Frame Interface: BB86 , BB92 • Bottom Bracket Shell I.D.: 41 • Defined Color: Black • Spindle Interface Type: Shimano Hollowtech II Threaded Model: • Includes 3 x 2.5mm spacers • Includes TL-FC24 adapter tool • Reduced size for light weight • New seal construction for smoother rotation • Requires TL-FC34 or included TL-FC24 adaptor for installation & removal • BB Shell Width (mm): 68 mm • BB/Frame Interface: English • Defined Color: Black • Spindle Interface Type: Shimano Hollowtech II • Weight: 77 g