dkjones, I read a thread a couple of days ago that explained this. A 1-1/4" receiver is used so HL can have a little more control over what goes in it. I believe they are concerned some yahoo will try to pull a car or boat if they put a 2 " receiver on the Lippert frame. I believe they are not worried about a bike rack. I believe this is what they had in mind, light stuff within reason and common sense. If it were me I would not hesitate to use an adapter for my bike rack. Search this forum to give yourself more comfort. By the way, my NBS GM truck has a 2-1/2" receiver ! I never knew they had this size. I bought adapters so I can use my 2" stuff. Tom