The Downhill hub pairs a 12mm thru axle and wide 15mm spacing for high speed riding and racing. At a light 236 grams, the rider can horse the bike around in the air. The strong, patented 6 pawl cam actuated engagement system handles constant pounding. The 12mm thru axle acts as a second axle making the rear end of the bike stiffer. Bill Shook’s design spreads the hub flanges very far apart, for optimal triangulation to build a solid wheel. The hub shell supports the bearings as wide as possible for maximum leverage and stiffness. The big 19mm diameter serrated steel drive side end cap grips the frame. Adjustable bearings and patented sleeve technology for improved bearing life.