We have tried the thin cheapo ones and they tear up. Also most are made for hang the bikes type rack. We are getting a new "sit upon" type hitch mounted bike rack. We bought an extra large grill cover for like $35 to put over the bikes when they are off the camper and sitting around in the campsite. We are going to get an upholsterer to make a custom fitted cover for the bikes while on the rack going down the road. In case you haven't noticed we like our bikes a lot and they were a bit expensive so we take care of them and can't afford new ones all the time. Our friends had a custom cover made. It is made from like backpack fabric and has a large zipper. Expect to spend around $300 for it. Theirs has lasted about 8 years now and still going. If you are interested, I think I have some photos of theirs which we will be showing to our upholsterer this summer. Will take bikes and rack on the truck over to them to do the work. I had a challenge finding an upholsterer who "likes a challenge". You can PM me and I'll go look for the photos in my computer.