The dt swiss 240s rear centre lock disc hub is a super light sealed bearing disc hub using shimanos centre lock rotor mounting for extra weight saving the forged aluminium hub shell and 15mm diameter aluminium axle keeps weight to a minimum and the star ratchet drive system in the freehub offers low maintenance ultimate strength and quick engagement 18 engagement teeth on ratchets make for a more positive pick up and the special coating on ratchets and axles massively improves lifespan fe