29" plus wheels using Duroc 40 rim (40mm outer/36mm inner width) with SunRinglé STR Tubeless technology. SRX Cartridge bearing straight pull hubs with a 3 pawl alloy cassette body and 24 tooth ratchet ring, yielding 72 engagement points. Built with double butted Wheelsmith spokes and alloy spoke nipples. Each wheel includes tubeless tape, valve and a 2oz bottle of STR sealant . Rear wheel includes XD and Micro Spline driver bodiesItem Specifications: Number of Holes, 28, Size, 29", Front or Rear?, Rear (XD/Micro Spline), Rear Axle Spacing, 12x148, Material, Aluminum, Width, 36mm, Weight, 1018g, Type, Tubeless, Color, Black, Hub Type, SRX, Rim Compatibility, Duroc 40, Model Name, Duroc 40 Expert, Brake Type, 6-Bolt,.