DT-Swiss 180 Straight Pull Center Lock Disc Hubs. Features: Ratchet EXP (36t) features a fused threaded ring/ratchet and single spring, reducing the number of components for a lighter and more durable freehub system Integration of drive side bearing into threaded ring widens bearing stance, resulting in 15% greater hub stiffness With DT's ratchet system, all of the teeth on each side of the ratchets engage simultaneously every time. This creates much smaller point loads and results in the legendary reliability of Ratchet System hubs Center Lock disc SINC ceramic bearings Refined end caps allow for easier disassembly