Way back when I was a rookie rv'r , I thought that it must be ok, they would not sell a product that did not work.. RIGHT ??? Well , on our first trip with the bikes mounted on the bumper I stopped for fuel , at that time I did my now normal walk around only to find the bike handles dragging on the ground,,, The whole bumper was pulled away from the mounts and only attached by about 1/4" of sheet metal..
It cost me 2 new bike handle bars , a new bumper , new mounts.. and was a royal pain because I had the bed filled with camping stuff and the cover all buttoned up... don't do it unless you reinforce the bumper....I Consider myself lucky,, they did not come off and create a major hazard for someone behind me . .