Need Utility Trailer Advice

[Weldangrind]

I need to replace my existing 4x8 trailer, and the new one must be able to carry two quads and two dirt bikes. I don't want a flat deck (too high), and I don't want removeable sides. I'm planning on a 6x11 or 6x12 layout with the wheelwells inside the trailer (like a pickup), and all of this will be built on a 2000lb axle. Before the rants begin, I know that it would be better to build it with a 3500lb axle and brakes, but I'm pulling it with a lousy minivan that is maxed out at 2000lbs. This trailer must also be able to carry a load of gravel, dirt, bark mulch, sand, drywall or whatever. I don't plan on ever loading it with more than 1100lbs.

I plan to use square tube for the frame rails, extend them out beyond the headgate and tie them into the tongue. The tongue will start just above the axle and will be welded at every available point. There will be 6' ladders that are welded across the tops of the frame rails every 16" or 24" (can't decide). I intend to use pressure treated ply for decking and box sides.

The questions I have are about square tube thickness. I'm not sure what to use for main frame rails, the tongue (which should likely be the strongest of all) and the ladders. I'm thinking of 1/8" wall for the frame rails and ladders and 3/16" for the tongue. The entire trailer needs to weigh less than 900lbs.

Any thoughts?

[nosnerd]

Re: Need Utility Trailer Advice

.125 wall is more than enough...16 inch centers please... use a st175/75r15 TRAILER tire on a 5 bolt wheel and 1 1/8 bearings...3/4 plywood is plenty strong

[fabricatordave]

Re: Need Utility Trailer Advice

a bunch of .125 can get HEAVY quick there is a size just below that that is strong enough for main frame and allot lighter
think it is like 14 ga 125is 12ga???


here is a chart you can come up with weight

http://www.rollformedshapes.com/gagechart.htm

[62-impala-ss]

Re: Need Utility Trailer Advice

I think I would use a rectangular tubing rather than square. Much more rigid.

[SuperBuickGuy]

Re: Need Utility Trailer Advice

900 lbs plus 1100 lbs is 2k.... you're living on the edge man.

[fabricatordave]

Re: Need Utility Trailer Advice

more weight info

http://mdmetric.com/tech/tubewt.htm

[squirrel]

Re: Need Utility Trailer Advice

steel weighs 0.283 lbs per cubic inch. It's not too hard to predict the weight.

I agree that 1/8" is probably overkill for most of the trailer, and I also agree that rectangular tube would be good for the frame.

If you can make up a sketch of the trailer design you have in mind, it would be much easier for us to evaluate it!

[Weldangrind]

Re: Need Utility Trailer Advice

Thanks to all you fine gentlemen who responded.

steel weighs 0.283 lbs per cubic inch. It's not too hard to predict the weight.

I agree that 1/8" is probably overkill for most of the trailer, and I also agree that rectangular tube would be good for the frame.

If you can make up a sketch of the trailer design you have in mind, it would be much easier for us to evaluate it!

Since I haven't figured out AutoCad yet, I'll have to make sketches in crayon and then scan them. Maybe my lovely wife will give me a tutorial; she took an AutoCad course due to her job at an engineering firm.

900 lbs plus 1100 lbs is 2k.... you're living on the edge man.

I know. Scary. I'm handicapped by the 2000lb minivan payload, until I can afford a truck. The quads and bikes (with an over-estimation) will be about 1000lbs. I'll likely have less than another 100lbs in it with things like jerry cans and tools. It's now my job to build a trailer that can serve the intended purpose without excess weight.

I think I would use a rectangular tubing rather than square. Much more rigid.

That's what the nice man at the steel shop said. He stated that the strength is derived from the vertical plane, not the horizontal (sounds logical). He recommended 1x2 rectangular tube for the ladders to save some weight; I happen to have a considerable amount that was free.

.125 wall is more than enough...16 inch centers please... use a st175/75r15 TRAILER tire on a 5 bolt wheel and 1 1/8 bearings...3/4 plywood is plenty strong

I'm with you on the 16" centers. I'll just need to adjust the size and wall thickness to compensate for the weight. I always use load range "C" tires on trailers, although I was thinking 13" or 14". A ST 175/80 R13 load range "C" has a capacity of 1360lbs, putting the total at 2720lbs, which is considerably more than my van can pull. I'm not sure of the bearing size in the axle I'm looking at, but the tube diameter is 1 3/4", the hubs are five bolt and the whole assembly is made in the USA. I plan to use 5/8" pressure treated ply that I will subsequently coat with copper sulfate.

here is a chart you can come up with weight

http://www.rollformedshapes.com/gagechart.htm

Thanks for the link; I'm off to check it out now. The nice man at the steel shop was also able to give me precise weights for specific tube sizes per foot.

Any thoughts on tongue thickness?

[outlaw57]

Re: Need Utility Trailer Advice

insted of having to deal with wheel wells, use short tires found on snowmobile tires, depending on load range they are good for 1000 lbs each.

[squirrel]

Re: Need Utility Trailer Advice

I'd try for 14 or 16 gage on the main trailer structure, and 12 gage or 1/8" thick on the tongue. The tongue will probably be 2x3 tube laid flat, or 2x2 square?

The tongue wants to go back to the middle of the trailer, and attatch to a crossmember there, and at the front of the trailer.

Also you could consider using angle to make the perimeter frame...my car trailer is made almost entirely of angle.

[Weldangrind]

Re: Need Utility Trailer Advice

insted of having to deal with wheel wells, use short tires found on snowmobile tires, depending on load range they are good for 1000 lbs each.

Short tires spin crazy fast on the freeway; I want to be able to pull the trailer to Edmonton if necessary, and that is a 1440 mile round trip. Thanks for the idea, though. This is what brainstorming is all about.

I'd try for 14 or 16 gage on the main trailer structure, and 12 gage or 1/8" thick on the tongue. The tongue will probably be 2x3 tube laid flat, or 2x2 square?

The tongue wants to go back to the middle of the trailer, and attatch to a crossmember there, and at the front of the trailer.

Also you could consider using angle to make the perimeter frame...my car trailer is made almost entirely of angle.

I'm leaning towards 1/8" for the tongue, but it will be welded at the cross member that is just above the axle and at every cross member along the way. I also intend to extend the frame rails out in front of the box, angle them and weld them to the tongue. I'm hoping for a very light and rigid structure.

Good call on the angle iron. I have a cache of thin 1x1.5 and 1.5x1.5 tube that will be used up first, then I might be inclined to buy angle if needed.

As a tip to my fabricating friends, free steel in various sizes is usually available every month at your local motorcycle dealer. They sell alot of motorcycles, but it turns out that nobody takes the crate thet were shipped in. :D I asked for permission at two local shops, and they've allowed me to take all the steel I want, as long as I don't make a mess. They just leave it stacked up behind the shop, hoping it will disappear. My 4x8 trailer was made almost entirely out of that stuff.