Front Hubs WEIGHT: 137 g APPLICATION: MTB BRAKE : Disc IS (6-bolt) AXLE SYSTEM : 15 mm Thru Axle BUILT-IN DIMENSION : 100 mm NUMBER OF HOLES: 28 Rear Hubs WEIGHT: 229 g APPLICATION: MTB BRAKE : Disc IS (6-bolt) FREEHUB :Shimano HG(8-11speed) Ratchet System: 36 SL AXLE SYSTEM : 12 mm Thru Axle BUILT-IN DIMENSION : 142 mm NUMBER OF HOLES: 28