The Krampus is the bike that started it all - the plus-size movement that is. For 2017, the Krampus features Surly's Gnot-Boost rear hub spacing of 145mm; compatible with Boost 148 x 12mm thru-axle, 142 x 12mm thru-axle and 135mm quick-release hubs. 100% Surly 4130 CroMoly steel frame and fork; double-butted main triangle and 44mm headtube New tube-set uses the same trumpet tubes found on 2017 Karate Monkey frame Gnot-Boost adjustable rear dropouts Internal dropper seatpost routing 30.9mm seat tube Designed to fit up to 29 x 3.0" tires Specifications Rear Axle 12mm Thru x 145mm Brake Type Disc TT (Effective) 660 Fork Type Rigid Fork Material Steel Frame Material Steel Frame Type Rigid Front Axle 15mm Thru x 110mm Color Sage Green Mfg Size X-Large Platform Krampus Wheel Size 29+ Defined Color Green