Bottom Brackets

- Simple and reliable square taper bottom bracket - Replaces both BB-UN26 and BB-UN55 - Sealed cartridge bearings - Cr-Mo axle - For bicycles equipped with a chain case, select BB-UN300-K - For E-type front derailleur compatibility, choose BB-UN300-E - Fixing bolts not included; Shimano FC-E6000 bolts suggested

Get the most out of SRAM's high-tech cranksets with the GXP Team Bottom Bracket. Built to last, this super-smooth bottom bracket lets your SRAM GXP crankset (sold separately) spin effortlessly without weighing you down.

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

- Left and right bottom bracket cups with standard bearings for FSA MegaExo cranks - BB-9050 is for 24mm spindle 68/73mm MTB K-Force and Team Issue cranks - BB-8681 for K-Force Light (a non-ceramic option) and SLK Light Road MegaExo cranks (BB-8681 bearing covers have been redesigned so that the spindle now rides directly on the bearing itself) - BB-7000 is for 24mm spindle 68/73mm shell MTB Gravity Lite, Moto X and Afterburner cranks - BB-7000 is for 24mm spindle 83mm shell MTB Gravity Lite cranks - BB-6200 is for 24mm spindle 68mm shell Energy, Gossamer and Omega No Bolt Design cranks - BB-6000 is for 24mm spindle 68mm shell Energy, Gossamer and Omega cranks - BB-4000 is for 19mm spindle 69mm shell Omega cranks - BB-1000 is for 19mm spindle 68/73mm MTB Gamma cranks - 1.37" x 24tpi (English threads) or M36 x 24tpi (Italian threads)

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.

Get more distance out of every pedal stroke with SRAM's BB30 Bottom Bracket Assembly. It features sealed bearings for a smooth pedal stroke and impressive reliability. Plus, it presses directly into your frame's BB30 bottom bracket shell for reduced weight and increased longevity.