Well as some of you may know I do a lot of dry camping (12,000 miles this year) and I drag my generator along on a cargo carrier hanging of the receiver hitch that was meant for a bike rack.
The poor thing kept getting lower and lower till the point I was scared it was going to start dragging. This, of course, happened 800 miles from the house.
As luck would have it there was a welding/truck shop near by and they hooked me up. The shop drilled out the holes on the bumper to 1/2 inch and replaced the "cheap" 1/4" bolts with "Class A" bolts. That immediately made the cargo shelf look a lot more level. Then they added a small plate to make it perfectly level and even painted it for a mere $40. That was service!
Thanks to Arch-Heli outside Rochester, New York for the great service.
So the moral of this story. If you are going to put more that 100 lbs. on the hitch, upgrade the bolts.