I researched this thoroughly recently when faced with whether or not to keep the fifth wheel I'd bought for my folks that they couldn't use.
I looked at two different solutions. The first and most obvious is to rig up a standard hitch setup under the fifth wheel. The drawback to that is a roughly 700 lb hitch weight
. It's ok if you have a full-size truck with a weight
distributing hitch, but still having nearly a quarter of the total weight of the trailer on the tongue is a little excessive. I called Scamp
and inquired about such a setup as I'd actually seen a couple of them, and they disavowed any knowledge of them. Actually they know about them, but wish they hadn't been modified into standard trailers.
The other setup involves using a tow dolly to support the weight of the fifth wheel gooseneck hitch, and then to pull the trailer. The dolly system has a couple of drawbacks; first it turns your trailer into a two-axle trailer like a Radio Flyer wagon or farm wagon and would be nearly impossible to back up, especially with a short tongue on the dolly. I had planned on making a dolly about 10' long overall with a 6' or so tongue.
The dolly itself would have been fairly simple to build. I'd spec'd out a Dexter #9 idler axle
, and the steel to build the dolly was going to run about $120. I was going to use 12 inch tall "C" channel steel to build a box on the frame, and then bolt the existing Scamp
hitch to the "C" channel, drilling extra holes fore and aft in the "C" channel to be able to move the hitch assembly forward or backward to adjust the hitch weight for the dolly. For backing, I'd figured I'd fabricate brackets that would attach to the ends of a receiver hitch on the tow vehicle, and then weld saddles onto the sides of the tongue frame. In between I was going to place solid bars that would act like idler arms to keep the dolly from moving from side to side while backing and effectively turn the dolly into a tag axle
for backing which would allow for normal trailer backing behavior.
I had ordered the steel and before I called to order the axle
I rechecked the State Code of Iowa and found that it's illegal to pull a two-axle trailer with a steering axle on the highway unless it's a farm trailer, or used in conjunction with a tractor-trailer setup.
So... there went my bright idea.