basic trailer build question

[Renze]

I have been toying with the idea of building my own utility trailer. Something that could haul my Kubota B7500 around as well as general material hauling. I figure the tractor w/ loader and attachments that I would take would weigh a total of about 2500 lbs. I wouldn't mind buying one of the many trailer plans but need a steel strength question answered first. I have an opportunity to buy 2x2 and 2x3 tube steel at a good price. I can get the 2x2 in either 1/8 or 3/16 thickness and the 2x3 in 3/16 thickness. Would any of these suffice to make a frame that is 6 x 12 foot with cross tubes every 2 feet? I would plan on getting a 3500 lb torsion axle with 15 inch tires. Obviously, if this works out it would mean a lot of pictures for you guys to look at and critique.

We used to build 3500 kg deckover tandem trailers of 60x60x3mm tubing, welded into a trussed frame. They were sought after by people that wanted to load 4 ton on them, weigh 5 ton (legally they would need air brakes and ABS at anything over 3500kg)

Basically, a 3500 lbs (1800 kg) axle would be O.K. on a trailer with the bed between the wheels. For a deck-over, you'd definately need a tandem for stability reasons.

Speaking from experience, under the right (wrong!) conditions, blowing a tire is a major problem even with a tandem weighing just 75% of the tow rating of your car...


Its bedtime here, but i can translate the imperial dimensions to metric, and figure out something if you have a basic sketch of your construction.

 

[jimmer2880]

about 5 years ago, I built a 6x10 utility trailer with a single 5,000 lb axle. I have hauled my Yanmar F15d (19hp Diesel, 4x4). It was ok if it was just the tractor & MMM. But, with the FEL, the axle was just too inadequite. Actually, it wasn't the axle, rather the tires. I made the mistake of going with 5 lug wheels. The problem is, that I can't get wheels/tires with high enough rating for the axle.

If I were to do it again, I'd go with a tandem (I may still convert it).

 

[Diamondpilot]

Common trailer axles in the US come in 1,200 1,500 3,500 5,200 6,000 pound ratings. Like others said I would not tow any machinery on a single for many reasons but one not mentioned yet is the size of the tires that would be needed to support 4,000#+ of trailer would be very tall and make it top heavy if built like a deck over.

I looked at building my own trailer back in 2004 and I could not get the axles, tires, lights, and wood for the deck for the price I could buy one for. That did not even include the steel. Do your home work but I would say if you do not have a bunch of stuff on hand for free you can not build one cheaper than you can buy one for.

Chris

 

[rdbrumfield]

I have built several trailers and flatbeds for trucks. for trailers I have used 2x6x1/4inch wall for the main frame. 2x2x3/8 angle for crossmembers. along the sides I use 31/2X2/8 flatbar with 2x4x3/16 tube for stake pockets. By putting these in the corner where each crossmember and siderail connect it reinforces it. Using 2x6 or8 for flooring it comes up for and even deck on top the crossmembers and leave spacing for chains to drop anywhere along the sides between the rail and the wood as the pockets are between.
The one I have now is 18ft long and 7and a half wide tandem axle. I put a hinged tongue so I can just come up to it with the tractor tilt it with the loader and climb on.
I like the flatbed instead of down between the wheels because loading/ unloading is so easy for logs and most anything. I don't believe I have seen a lowdeck that is over a month old that doesn't have the fenders dinged.

 

[Renze]

I have been toying with the idea of building my own utility trailer. Something that could haul my Kubota B7500 around as well as general material hauling. I figure the tractor w/ loader and attachments that I would take would weigh a total of about 2500 lbs. I wouldn't mind buying one of the many trailer plans but need a steel strength question answered first. I have an opportunity to buy 2x2 and 2x3 tube steel at a good price. I can get the 2x2 in either 1/8 or 3/16 thickness and the 2x3 in 3/16 thickness. Would any of these suffice to make a frame that is 6 x 12 foot with cross tubes every 2 feet? I would plan on getting a 3500 lb torsion axle with 15 inch tires. Obviously, if this works out it would mean a lot of pictures for you guys to look at and critique.

Converting to Metric: 3/16 is 3.175mm so a 2x2x 3/16mm would be allmost equal to a 50x50x3mm tube. In that case you would need the 2x3x 3/16 tubes as main runners of a spaceframe, spaced a foot apart, with lots of vertical and diagonal 2x2x 3/16 inbetween.
For the diagonal you could also use 2x1"

With this bridge structure as main frame runners, you could still decide to weld the crossbars on top of it (deck-over) or between the lower tubes (lowdeck)
If you use a bolted torsion axle, just weld some bushings into the tube to support the bolts, or they will squeeze the tube. Using flatbar to strategically reinforce the upper and lower tube walls where the axle is bolted, is another option. Best would be flatbar on the underside, supplemented with bolt support bushings.

 

[David Devuono]

Seems everyone is turning, the building of a trailer required to carry a B7500 into a tank hauler. B7500 weights 1400 lbs with ROPS, add 500 for a loader= 1900 and another 600 for attachments (thats a heavy attachment). B7500 is 7.5 ft long so 12 foot trailer should do. You need to start with your Tow vehicle, how much can it tow? How much tongue weight can your vehicle carry? If you have your B7500 with loader and scraper blade, you might be 2200 lbs, with a 3500lb axle and min 10% tongue you can carrier 3850 lbs-2500 lb load leaves 1,350 for weight of trailer. If you design your trailer with some metal on the sides welded to the frame, this adds to the frame strength. I think 2x4x1/4 is overkill unless you will not have any sides on the trailer, like a car hauler. If you are looking at something like the trailer I built for my smaller B4200 with FEL and I used 2x2 1/8 on the body and ended up with doubled up 2x2 x1/8 on the tongue. Many years of use and I was not hauling a boat anchor when empty.

 

[towmotor]

Gotta go with Dave here.

I built a car hauler using 4 x 7 lb channel for the frame rails, crossmembers and tongue frame, 1.5 x 1/4 angle to support the planks and 2.5 " sch 40 black pipe for the (tandem) axles. (I had to truss those)
The whole thing, soaking wet (and no load) weighs about 1100 lbs.

What have I hauled with this thing?
Cars and other junk, weighing alot more than 2500 lbs.
I once hauled 2.5 cords of firewood on it. I nearly choked when, later, I happened to see a chart outlining the weight, by cubic foot, of most common firewood species...2.5 cords... 10,000 lbs!
No wonder the little 1/2 ton Dodge was down in second gear up those hills

I got home alive. My house is still mine.
Of course I would never knowingly do a thing like that again; the point is that the trailer held up under a load that nearly had the truck dropping a 'nad.
2x3x3/16 tube is inherently alot stronger than the skinny channels that make up my trailer.
I would definitely recommend using tandem axles with a spring equalizer.
It'll tow better and be more forgiving of a screwup like me.

If you're more comfortable getting engineered drawings, by all means do so. No matter what anyone in here says about it, we don't have to pull the thing. You do.

http://www.elamtrailers.com/plans.htm

20 bucks for trailer plans!

 

[Renze]

Seems everyone is turning, the building of a trailer required to carry a B7500 into a tank hauler.

The B7500 might weigh just a little, but whats the tow vehicle ? a half ton or bigger truck ? then you're going to need extra capacity because with a truck, you're going to overload a small trailer because you dont notice the weight. Once you have a trailer, there is so much more to tow than just that little kubby...
Also, they are advising 2500lb axles... reason to beef up the frame accordingly.

The construction i described is comparable to the construction we used for 3500kg tandems, or 7000lb. I think any pickup truck will still laugh at that weight. I have towed 4500lb with my Volvo 850 (3000 lb) and thats the weight it takes to notice a change in stability of the car (if properly loaded)
With a 5000 lb pickup, you would be hauling 7000 before getting the "feel" that your trailer is really loaded.

Making a truss frame of the 2x2 inch tubes is enough for 2 ton GVW, but when he wants to utilise the tow weight of his truck (and in time he will) the 2x2 tubes are too light. The 2x3 might be a little overkill, but definately a better choice than the 2x2"

Next to that, a beefy frame and towbar tow much nicer because of the absence of vibrations and swivel.

 

[Oldmax]

Don't ever build a trailer that size with a single axle. You won't like the way they pull. Make it a 16' With brakes on all 4 Wheels then you will have something you can use. The place I bought mine from sold the 12',14' & 16' for same price. You can buy a tandem axle cheaper than you can build one, If you figure your time as wages. I have done both. When you build a trailer and list you as builder you are held responseable for that trailer the rest of it's life . If some thing breaks and causes a wreck you are the one they come after. Not the one that over loaded it & abused it.

 

[rdln]

http://www.tractorbynet.com/forums/build-yourself/122517-can-done-trailer-building-question.html

A very similar post for reference.

Send me PM maybe I could use a good deal on that material too