Yeah if they are folding put em inside?I personally favor inside stoeing that way you know they are safe.II used to carry them on rear for a couple trips but was uncomfortable not being able to see them.Not because I was worried of damaging my camper but because I was worried I would kill someone behind me and not know it.f they werent folding I would tell you how we carry our four bikes securely inside our trailer.Pin box carriers are the only outside option I would do but decided against it because the bike get plastered with bugs.Seen it first hand.