Wheels Manufacturing T47A Bottom Bracket Putting The A in Asymmetrical The bottom bracket is the piece on your bike that the crankset goes through. With an excellent bottom bracket, your pedaling will be much smoother. The Wheels Manufacturing T47A Bottom Bracket features thread-together machined aluminum cups and internal Enduro ABEC-3 bearings. It is designed for Cervelo, Factor, and Felt frames with T47A bottom bracket frame interfaces. Features Includes sleeve to fit between cups for added protection from dirt and grime Machined aluminum cups are durable and lightweight For use with 24mm, 29mm, or 30mm spindles | Wheels Manufacturing | T47A Bottom Bracket 29Mm Spindle