The SportRack upshift plus is a rock-solid upright single roof mount bike carrier with easy to use clamp design. It mounts directly to most factory and aftermarket rack systems (max. 3.5 inch crossbar diameter) and fits bike frames up to 3 3/8″ in diameter and tires up to 2.6″ wide. The self-adjusting jaws automatically wrap around the downtube for precise frame hold, and the large wheel trays hold your bike securely during transit. A lock is included to secure the bike to the carrier. The SportRack upshift plus is a great choice for anyone looking for an easy to use, reliable roof mounted bike carrier.