My TT does not have a rear bumper.  It is a molded fiberglass rear cap……I would like to add a box bumper to it but do not have a clue where to start.  The under belly is all enclosed so the frame is not readily available .  It needs to be hollow so I can put a spare tire carrier and a bike rack on it….Trading campers is not an option to get a bumper…..

 Hi, I'm sure it can be done, but adding a rear bumper, a rack, a spare tire, and a couple of bikes might off set your tongue weight too much. [especially on smaller trailers]

First of all, a trailer without a rear hitch was not intended to have a hitch if you asked the manufacturer. However, there are plenty of success stories of modifications beyond what the manufacturer says, that are quite successful when done correctly.

I know of quite a few people that have done this mod. The hitch receiver is mounted to the frame and drops down so that it extends under the rear molded end cap and out the back to allow a carrier, bike rack, whatever to be added. The recommendations include:

Measure carefully so that if you want to maintain the underbelly covers that holes are created to allow this new hardware but still keep the underbelly sealed.

The hitch receiver must be installed by someone in the know that can weld or install the proper amount of support and with the proper fasteners (welding, bolts, both, etc.) to support whatever will be on the hitch. There's more to it than going to U-Haul and slapping on a bolt-on. The RV frame is already carrying the tonnage of the trailer so there will be more to consider for a proper receiver frame.

Some have added a receiver system good enough to tow a boat, vehicle or another trailer, but I have heard that some of these didn't work out (weld cracks or frame problems), but there are certainly enough owners who have done okay because they were shored up properly.

For convenience a Class III/IV 2″ receiver is installed but don't plan to use that much weight, unless you can maintain the structural integrity of the frame and receiver. This allows most bike racks to be used with additional adapters (which can add weight and movement).

Do not carry much weight, some say no more than 200 lbs including receiver and accessories. Otherwise you might affect the pin, but depending on how much weight. I have almost 20% GTWR at my pin and if I was so inclined and I did this I don't expect it would change much. But it is definitely something to be aware of and check.

Make sure whatever is attached is rock solid. Any movement is greatly magnified when traveling and bouncing down the road and this will create a great deal more stress. For example, if carrying bicycles, each one must be strapped down snugly and then the bike rack firmly installed in the receiver - there are bolt on accessories to help with this. I have followed trailers with bikes and racks on their trailers and it's very obvious when they are strapped welll and when they're not. Over time the stresses are sure to cause a problem.

Then post your mod after it's done so we can all admire it.

Bob Vaughn said:

My TT does not have a rear bumper. It is a molded fiberglass rear cap……I would like to add a box bumper to it but do not have a clue where to start. The under belly is all enclosed so the frame is not readily available . It needs to be hollow so I can put a spare tire carrier and a bike rack on it….Trading campers is not an option to get a bumper…..