Traxxas X-Maxx Sledgehammer Pre-Mounted Tires with 17mm Hex. The Sledgehammer tire was designed for 8S use and provide extreme traction and control in off-road terrain. The Sledgehammer’s 8.4″ overall diameter provides additional ground clearance, while the open block tread design clears mud and debris for great traction in loose surfaces. Package includes two pre-mounted tires intended for the Traxxas X-Maxx.