Rotor BB Press Fit 4624 RD Steel The Rotor BB Press Fit 4624 RD Steel easily accommodates your bike of choice with the press fit, 46mm diameter and 24mm axle BB shell. The Rotor PF 4624 Steel Bottom Bracket is part of the company's UBB System, which allows far more cranks to work with basically any frame. In this case, this BB allows for the installation of a Rotor 3D24 or Shimano 24mm crankset. Specs100% CNC-machined, 7075 aluminum shell for increased durability Silicone seals and center sleeve to prevent dirt ingress Designed to work with ROTOR and Shimano 24mm cranksetson a PF30 bottom bracket shell | Rotor | Bb Press Fit 4624 Rd Steel Pf 4624