If the thought of traveling without your bikes in tow is enough to make you cringe, then the Thule DoubleTrack Pro - 2 Bike Hitch Carrier is the solution to your cycle-less travel anxiety. We like that this rack attaches to either 1. 5- or 2-inch receiver hitches and carries two bikes, so you can bring a friend along, or bring your road and mountain bikes for quick singletrack sessions between between road rides.