On our 1991 Bigfoot
17 we carry our bikes on a lightweight over-the-spare bike rack. With our 1986 Bigfoot
we had problems with the spare tire mount breaking and needing welding and reinforcement but not with the bumper. On the 1991 the bumper metal tore just behind the weld that attaches the bumper to the frame. Both port and starboard sides tore. The welds were fine.
We had a welder cut a square of plate steel in half diagonally, creating two triangles. These triangles were welded top and bottom to the frame-bumper interface. End of problem we hope.