DT Swiss 240 EXP Classic Flange IS 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 6-bolt disc Steel cartridge bearings Refined end caps allow for easier disassembly DT Swiss spoke calculator: https://spokes-calculator.dtswiss.com/en/calculator Specs: F R:rear (XD) 54t Axle Spacing Mm:12x148 Boost Hole:32h Color:black/red Weight:225g