I find that hanging bikes as close together as possible is a lot more likely to damage the paint than the wheels. I have a fair amount of foam pipe insulation that I have on hand to pad bikes for shipping with and seem to get a steady amount more with each bike I buy. Suddenly the idea of how to store the pipe insulation and prevent paint damage while storing bikes all came together. I now put pipe wrap on the bikes that hang in the most congested and back areas (bikes I am not riding a lot). It solves the storage problem for the insulation and also protects the bikes. It only takes a minute to snap these things on or off the bike.
My hope is that they will not absorb and hold moisture...other than that I see no down side to it.
Tom Sanders
Lansing, Mi