Bottom Brackets

• 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

- Tiagra-level Hollowtech II bottom bracket - Compatible with all road Hollowtech II cranks

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

Compared to the power transfer of the conventional square taper spindle, the 8-splined OCTALINK interface that connects the bottom bracket and crankset increases the strength and rigidity for the entire assembly.

Shimano BB-ES51 Octalink V2 Bottom Brackets - Fits Shimano Octalink V2 Spline Cranksets - Crankarm fixing bolts not included