The Karate Monkey features updated, progressive trail geometry, our custom trumpet tubeset and Surly's Gnot-Boost rear dropout system. Available in a variety of colors, with multiple drivetrain and wheel size configurations. - 100% Surly Chromoly steel frame and fork; double-butted main triangle and 44mm headtube - The tubeset uses the same trumpet tubes found on Instigator 2.0 frame - Adjustable rear dropouts with 145mm Gnot-Boost spacing. Works with 142, 148 12mm thru, as well as 135mm w/ 10/12 washer - Internal dropper seatpost routing with 30.9mm seat tube ID - Clearance for 29 x 2.55 or 27.5 x 3 tires