You are in the same boat as we are. Had a hitch on the 2011 3400 and now no hitch on the new 2014 3725. I don't see any way practical to install one either, as the frame is completely enclosed with the plastic sheeting/insulation. I'm not willing to cut holes in that and expose things. Some people have made bike racks to fit the king pin bracket, others have made them for in the truck bed, some hang them from the rear ladder (not a good idea in my opinion) and a few have had a receiver hitch installed on the front of the pickup, and hauled them there. I think that is what I would do, if I'm going to do it. I never did like the bikes on the rear hitch, and had to reinforce the rack on the old rig so it wouldn't do the "dance" going down the highway. One othe option that some have done is to carry the bikes inside the trailer, IF you have room. Perhaps I'll start doing more walking, instead!!!
Hybrid Mode
