Riders building or servicing a road bike with a 68 mm English-thread shell and a HOLLOWTECH II crankset.
The BB-R9100 is Shimano's Dura-Ace threaded HOLLOWTECH II bottom bracket. Small ball bearings keep the weight down, and an advanced seal construction gives smoother rotation. Shimano lists an average weight of 65 g, with anodised aluminium adapters.
Shimano makes it for both 68 mm English-thread and 70 mm Italian-thread shells. This one is the 68 mm English-thread set, where the right-hand (drive side) cup has a left-hand thread. Grease both cups, fit the inner cover and tighten to 35 to 50 N·m with Shimano's cup tool.
Small ball bearings
Shimano uses small ball bearings to keep the bottom bracket light.
Advanced seal construction
The seals are designed for smoother rotation.
Anodised aluminium adapters
Light cups with an anodised finish, for HOLLOWTECH II cranksets.
Dura-Ace pairing
Shimano lists it with the Dura-Ace FC-R9100-P crankset, and as the recommended threaded bottom bracket for the FC-R9200.
Fit
Build and install
Great for
Maybe not for
Check that your shell is 68 mm wide with English thread. The 70 mm Italian-thread version is a different part, and its right-hand cup has a right-hand thread instead.
Grease the cups and fit the inner cover
Shimano's manual says to grease both cups and always fit the inner cover, or the waterproofing gets worse. Tighten the cups to 35 to 50 N·m, and if you ever feel looseness in the bearings, replace the bottom bracket rather than trying to adjust it.
