apratt wrote:Mike, I can't see where there be any problem in making the ultralite into a 5 foot wide trailer?
I can't either. The only things that the extra width affects are the roof spars and the floor.
As I remember the Ultralight has a single skin roof, so the strength of the roof spars is quite important. On a 5ft span, even close-spaced 1x2s (with the 2 vertical) sounds a bit weak to me, but 1x3s sounds over the top, so maybe it's 1x3s cut down to 3/4"x2" actual.
As the floor is a sandwich panel, I don't think the 5ft span is any problem - Mike drew 1/4" ply top and bottom which I think is probably overkill! My only concern would be the point load on the front of the floor if a single tongue is used - using a piece of oak (of the same size) instead of softwood would address that.
I can't see any problem with the axle on a 5ft wide - except that you can't use a HF trailer kit. Either torsion or leaf spring would do, though I would have a preference for torsion as it provides a strong cross-member for free.
On the subject of the axle, I have now seen a couple of places where it clearly shows that in full-beam torsion axles, the rubber goes nowhere near the middle, so Mike's original idea of welding a single tongue to the middle should work fine - though as I mentioned before, I guess you can kiss goodbye any warranty on the axle. I still prefer an A-frame for the lower load it puts on the body.