<p>Laying the bikes on top of each other, even with a blanket between them, is not a great idea. Deraileurs get bent or knocked out of adjustment, brakes get knocked off center. It’s not simply a question of scratches or chipped paint. In the world of racks, a roof rack is the way to go but is expensive (about $600 for a 2 bike system). For transporting inside a SUV, the seat back mounted fork clamps I mentioned are the way to go and are economical ($70 or less for 2).</p>