This is what I bought. It attaches to the square RV bumper.
It is designed to also carry or go around the spare tire, but I just moved my spare to the right side and bolted this on the left. The empty space where the spare would fit makes a good spot for the lawn chairs and the bikes in front. Mines is over 8 years old and looks like the day I bought it. I carry ALL kinds of stuff on that rack!!
You can pick them up at any RV store or dealership parts dept.
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video how it works and attaches to RV.
http://www.etrailer.com/RV-and-Motorhome-Bike-Racks/Swagman/S80500.html