The Surly Rear Disc Rack is made of tubular CroMoly steel and is specifically designed to fit frames with seatstay-mounted disc brakes like the Straggler (650b and 700c), Krampus, and Karate Monkey. Features: Tubular CroMoly rack, stainless-steel hardware Height-adjustable to accommodate 26-29" wheels Hardware housed in reusable Surly Tool Bag NOTE: The following "RK" part numbers will not be compatible with the new Rear Disc Racks: RK013, RK0121, RK0134 Specifications: Maximum Wheel Size (in): 29+ Requires Eyelets: Yes Disc Brake Compatible: Yes Platform Dimensions: 13.77 x 5.90 Material: 13.77 x 5.90