Some eccentric bottom brackets require up to seven pieces to operate, and they require regular service to prevent a creaky ride. Niner's ingenious design has three parts -- it doesn't get much simpler than that. The most important aspect of Niner's Bio-Centric EBB system is the way it secures itself to the frame. Instead of expanding from the inside of the shell or relying on set screws, the EBB closes against the bottom bracket shell. This effectively locks out noise-causing contamination, while reducing stress and deformation to the EBB or frame. The Bio-Centric EBB is compatible with all Niner frames that use a 55mm diameter and 68mm wide shell, including generations that use the set-screw-dependent EBB. When installed, it will use a standard 73mm bottom bracket. The Niner Bio-Centric EBB is available in Black, Blue, Red, and Silver. If you're upgrading an early frame, remember to seal off the existing screw holes with silicone to prevent contamination.