We get this question about every month or so. There are about 50 threads here and a search will explain why it "might" work on an older full strength frame trailer (like a horse trailer) but not on today's lite or ultra-lite campers.
The bumper is like paper and the welds are there to keep it from falling off (barely). There have been reports of the bumper falling off with just the spare tire on it.
The frame mount type has been known to cause frame cracks just behind the axle mounts due to extreme flexing of the I beam (made from 3 pieces of thin steel welded together and not a single extrusion) by the bike rack (or generator rack) bouncing (no shocks on the camper).
Please search "bike racks" in the FRF green search box.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW