Tuesday, 13 March 2012

Got Any Draw?

I'd all ready made one new set of chassis mounts to
account for the trailer getting wider

My Dad was down last weekend and we were standing around the trailer, cups of tea in hand, discussing the various options open to me concerning different aspects of the build when I thought it would be a good idea to loosely fit up the draw-bar (A-frame) to give us a better idea of where it would pass beneath the intended line of the runners so we could get a better idea of  where the runners could get some extra support. It hadn't occurred to me , but he instantly expressed some concern about the about the large distance between the leading edge of the trailer and the hitch. This is due to the fact that is was of course a caravan chassis, so a long draw bar was necessary to accommodate the overhang and wide front of the caravan body as well as the gas bottle box and still permit a decent turning circle, and a caravan being very light would not put too much strain on a long, un-supported draw-bar and would not become too nose heavy, a full ton of car would be pushing it.

The obvious place to take it back to would be the first cross bar just in front of the X section (top left of the picture) but that would have brought the hitch too close to the trailer (not enough room to turn). after much discussion and another cuppa it was decided that making an entirely new set of mounts on the chassis and the draw bar legs was too much hassle just to move it back 1/2 a foot so we agreed to leave it where it was.

But after a couple of days of to think about it I had to concede it was going to need doing.

The bracket passes beneath the side rail for
 extra vertical strength
Support from behind to counter any 'Pull' forces.

Sunday morning came along and out came the welder. The first job was to measure up and fabricate some new chassis mounts. the best place for the new mounts to go was about 500ml in front of the cross bar and 65ml in from the side rail. 30ml angle steel was the weapon of choice as its just as stiff as box section over short distances and you only have the one surface to drill through. An extra piece of angle was added to prevent the mount getting pulled forward too hard and I might yet weld in another piece to support it from beneath as this part of the draw bar is pulling the bracket down due leading edge of the trailer acting like a fulcrum to the hitch getting pushed up by the tow-ball.

Next  up were new mountings for the draw bar legs themselves. Pretty straight forward but they needed some carefull measuring up to get the holes in the right places. I just about had time to get a coat of paint on everything as it was going dark so it was a whole days work (not including a 3hr surf break) to move the hitch back about 8 inches, but at least I can sleep at night and the poor old Audi can have an easier time of it.

Boom! a few inches make all the difference