The Yakima WheelHouse wheel holder mounts to nearly any crossbar and holds one wheel. It fits QR wheels from 24-29" out of the box and can be used with the optional thru axle adaptor for 12/15mm thru axles. Features: Folding design allows it to fold flat when not in use Fits wheels up to 29" in diameter and 3" wide Compatible with various crossbar designs using the SpinVice clamp Compatible with the SKS lock system