Rhythm "Big Outboard Bearing" bottom brackets are external mount integrated bottom brackets where the bearins mount outside the bottom bracket shell allowing the bearings to be bigger. This creates less pressure on the bearing allowing them to spin better. Designed to work with all Rhythm cranks as well as any external bearing type crank set such as Shimano DXR, DK Flash and many others.
CNC Durable Forged aluminum cups
BSA1.37"x24T for MTB, FR, DH to fit 68mm and 73mm bottom bracket shells