Originally Posted by JonathanGennick

My approach (photo below) is to Gorilla-tape some cardboard to the part of the trunk where the pedals hit. It is a solution born out of desperation the first time I tried to hang three bikes from the rack. It's too easy to forgot to position the pedals precisely, and my car's paint has suffered some pedal-dings over the years. My rack has three positions, and I always use the outermost one when I'm by myself. I try to avoid more than one friend at a time, so that I can avoid using the innermost position.