Hey Andrew, You can cut two small pieces of carpet and fold them over, make a hole for the beam bolt in each one, and then attach them to the inside of the ends of the traveller. The car will slam into that instead of the bolts and they are easy, cheap, effective bumpers. I do use the traveller knot trick to prevent it in the first place so this is belts and suspenders. Anything to prevent or control the slamming is a good thing.