trailer build ?

[gwhammy]

I've got a partial trailer frame made that was going to be a gooseneck but I'm really needing another heavy pintle hitch trailer. The main beams that are put together are 4 inch by 12 inch tall tubing .250 thick that are 25 foot long. I've plated the bottom of each with 3/8 by 3 inch strap that was heated before welding to put tension in it. These are already a frame set up for duals. I'm wanting to put a 6 foot dovetail which would make overall length 31 foot.

The axles that I have are air ride 20,000 lb. axles, putting three under it like the current pintle hitch I pull. The dovetail will have folding ramps with feet to take the load off the rear like the current trailer.

Tongue load is probably around 8000 to 10,000 lbs. with around 43,000 lbs. on the axles which is legal on a 97 inch center to center. The pintle hitch I pull now handles pretty decent I just can't have it down long and it needs some rebuilding and new airbags soon.I'm also wanting a little longer trailer so the bobcat and backhoe fit on it better.

I guess my question is the tubing, most of the load sets over the axles but someone told me the tubing has a chance of cracking. I've built alot of trailers with I-beams but this would be a first with tubing and this kind of load.

[smalley]

I wouldn't be that worried about the tubing cracking. But you will need to plate the sides of it where you mount the axles or it might start to crush the tubing in that area. Make sure any plating you do is angled or pointed on the ends or it might create a place for it to crack.

[gwhammy]

Well, going to use the frame. The axles are welded to it and have the air bag mounts made. If you figure each axle has 4 contact points and three axles that is 12 points. Max load on the axles is 43,500 dot legal wt. figures out to 3625 lbs at each point. Each point is around 8 inches long with two gussets 7 inches long extra. That would be 22 inches of weld which would be about 165 lbs. per inch of weld. Maybe over simplified but I think as long as the stress points are plated it will work.

The worst spots I've seen on the pintle I have are the break over point on the dove tail and the spot the ramps hook. With the 43000 lbs. loader all of that weight balances on these points.

[ENafziger]

Put up some pics! What do you use to pull this?

[08BIGRIG]

Very cool bud. Pics by any chance?

[gwhammy]

I'm not very good with pictures or the internet but I will try. I have the axles welded in and mounted the dozen 17.5 tires saturday. I'm kind of slow on projects, the center section of this frame was put together about 4 years ago to make a gooseneck.

It will probably be a dovetail but I'm looking into maybe making a 10 hydraulic tail on it. I've always wanted a hydraulic tail trailer, but can't decide. A dovetail with manual ramps are simple.

The truck is a simple fl112 freightliner dumptruck with a 400 horse m11.