Bottom Brackets

BB-UN26 cartridge bottom bracket. - Smooth rotation - Square taper spindle - Sealed cartridge bearing assembly

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

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.

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