Heavy Trailer: how would you make a 10/14K dual purpose trailer?

[Jim Timber]

I'm starting to think about designs for a dual use heavy flatbed. I need something to haul my tractor (7100# without implements), and machines weighing up to 10,000#, but also bunks of lumber and whole logs. I have a Class 6 Chevy straight truck that can pull 10T, so that's not an issue. What I'm wondering is if it's possible to make a 7T trailer that's light enough to serve dual duty as a 5T behind a 3/4T truck?

Most 5T trailer builders are using 6" channel for the main frame rails. What if those were replaced with some heavier wall tubing in the 3/16-5/16" range? Could the weight saved from the flange flares be better utilized in the walls of the tubing? I know cost will be higher, but I should be ok vs buying when I don't factor my labor.

Suspension or no suspension? Cost, weight, complexity - is it worth springing heavy equipment and building supplies more than just sidewall flex?

Those who've built these in the past: what would you do differently than what you did, and what have you added that you've found invaluable?

As usual; any insights and discussion will be greatly appreciated!

Thanks!

 

[Shield Arc]

With square tubing there is always the rust issue.
How about a removable gooseneck adapter?

 

[bcp]

Suspension: Yes. I've seen empty unsprung trailers on the highway bounce over a foot high on one side when hitting a pothole. And if it is a two-axle unsprung trailer, you will have many times when all the weight is in one axle, and even with both on the ground, the weight would almost never be equally shared. I would only have an unsprung trailer for low speed farm use and at tractor speeds on the road.

Bruce

 

[George2615]

If you build it as 7T you should have no problem towing it with a 3/4T truck. I have a 14K tilt bed trailer (rated for 10,300 load) and a 13,8K dump trailer (rated for 10,000 load). Both trailers weigh under 4K and I tow them with a 1/2T truck rated to tow 9600 lb. Of course when towing with the half ton the trailers are never at max load capacity. Each trailer usually weighs around 8500 loaded in this case.
It should have suspension. Building out of heavier steel will easily put your trailer weight well over 4K (probably closer if not over 5K empty).

 

[Jim Timber]

With square tubing there is always the rust issue.
How about a removable gooseneck adapter?

My C65 will have a 5yd dump bed on it as soon as I'm able to shorten the frame. These will be bumper pull - maybe with a lunette ring.

Gooseneck is a nice idea though.

Rust with tubing is a valid issue as well.

I'd like to keep this as light as possible for obvious reasons, but that's probably not going to make it a feather-weight trailer no matter how much I try.

 

[Jim Timber]

This one's @2640# for a 7T.

HSL16 - 7 Ton Capacity Equipment Trailer

I'll have to see what they're charging for that as it's very attractive.

 

[Shield Arc]

Gooseneck is a nice idea though.

I've made a couple of these so far. A friend of mine wants me to convert his gooseneck dump trailer so he can remove the gooseneck, and go to bumper pull.

 

[Jim Timber]

What do you end up gaining other than better weight distribution and turning radius?

 

[Rustyiron]

I've been pondering the same thing Jim, sometimes I just don't need my goosneck and in my situation, it involves removing the rear sideboards and tailgate from my 450 dump. I'm starting to think that buying an old(er) used 10t. and replacing the tires, suspension, wiring if needed and a new deck. It seems that the paint job on this class of trlr does a good job of staying on and fighting the rust, and usually was owned by a contractor that is not dragging it around all winter in the nasty weather (salt). I prefer a dual tandem set up and have not priced those axles new yet, but it's looking like the $2500-$3500 that I see now & then go's a long way in frame metal and axles, not to mention priming & painting vs. a quick paintover if possible.

 

[Jim Timber]

These are also on my radar, but they don't list curb weight.

7 Ton Equipment Trailer | Johnson Trailer Co.

 

[Shield Arc]

What do you end up gaining other than better weight distribution and turning radius?

They do turn nice and tight. Another big advantage is you can put so much weight on the rear axle of the tow vehicle.

 

[jenkinsph]

This one's @2640# for a 7T.

HSL16 - 7 Ton Capacity Equipment Trailer

I'll have to see what they're charging for that as it's very attractive.

Looks good but is built a little light for me. I would rather buy one that weighs closer to 4,000 lbs. in that length. The ramps look light enough to bend with a heavier tractor.

 

[ultrarunner]

This one's @2640# for a 7T.

HSL16 - 7 Ton Capacity Equipment Trailer

I'll have to see what they're charging for that as it's very attractive.

Find out anything price wise?

 

[Jim Timber]

No, I haven't found anyone claiming to be a dealer either. No listings on truck trader.

I'm not sure how I'll proceed. Need to do some digging on parts costs and materials and see where it comes out. Used stuff this size is rusty crap by the time they're sold and they still want what the steel costs for it.

 

[dstig1]

Have you looked at Felling? Local(-ish) and they seem really well built. Not terribly cheap though...

 

[Jim Timber]

Felling's the norm in rental fleets around here. By the time those trailers get sold, they're not cost effective to be fixed.

I had forgotten about United though. They've been pretty reasonable on used stuff and turn over equipment with more frequency. I should see what they've got available. I should also look at the Williston CL offerings now that the oil boom is imploding.

 

[Tractor Seabee]

Us armchair engineers tend to over build to be safe which raises the material cost. Trailer Manufacturers have engineered designed that minimize material cost and controlled manufacturing conditions minimize labor cost. If you honestly add up all your costs to make your own and compare with a factory built trailer that is certified you may well buy a new one.

You do not want to be in the positions of a home built trailer that has a structural failure resulting in a legal action. You are in a negative position with no back up from a manufacturer with deep pockets. it is the old cliche of "cover thy ### with paper (structural certification)".

Ron

 

[Jim Timber]

I'm not worried about failures, but then I also have appropriate insurance.

 

[Mysfyt]

Jim, I've built a couple of trailers using C8x11.5 for the side rails and 2x4x1/4 angles for the cross beams which supported the 2x10 treated lumber for the deck. They are tandem axle with springs and equalizers and it came down what the tires could handle as far as the load limit. The bed was about 16' long. I wish I could send you a picture but they are both out on 'loan' to a friend and my brother.

I'm positive this design would work for you just as good as it did for me. The axle spring perches would determine the width. Some food for thought.

 

[Jim Timber]

I think I'm going to end up buying the first one after all. I did some deeper digging and have some options in the area that look good.

Once I find out if I get my new truck next week, I'll get serious about the trailer.