Ancra 49288-10 Extra Mount Track Star Accessory Mounting Kit Patented, lock n load system using high strength aircraft-style track provides positive attachment to your bike hauler Designed to fit front tires 3.5in. to 5.5in. wide Reinforced, powder-coated, tubular steel, solid base plate Designed to fit standard truck beds and flat floor trailers To install, position chock stud feet into track, press down and slide chock forward