Trailer Steel Sizes

[fseider]

One thing I've found in my research is that I'm just not smart enough to decipher all of the recommendations concerning the steel sizes to use for a teardrop trailer in the 1000-1200# range. (4.5 X 9 ft) This is a tough topic it seams! I've found all over the web suggestions by people explaining what size steel they have used to build their trailer, but I can't seem to find anything somewhat definitive as to the proper size that should be used.
My goal is to have a nice strong trailer for a teardrop, say something that is good up to 1500# to be safe, to build it as light as possible, but at the same time not be overkill and adding extra weight to the TD. Is there any definitive information or source anyone is aware of that will be fairly straightforward about steel sizing? I know I can, for example, use 3X3 1/4 square steel tubing for my trailer, but that would be overkill for a 1000-1500# trailer. How do you guys n gals know what size steel to use without going overboard and adding unnecessary extra weight?

Thanks in advance,
Fred

[bobhenry]

This is exactly why we try and refrain from discussing politics and religion on this forum. Frame size will be the next great argument ..........

Opinions on the optimum frame should run from PVC to rail road rails and many more ideas in between.

A good answer is as close as Lowes or Tractor supply just look over the 5x10 utility trailers out front if you are using a sprung axle.

a torsion axle places a bit more of a point load in 1 spot on each rail while a sprung axle places it in 2 points about 16 to 18 inches apart.

So there is your 1st fork in the road.

Now torsion box floor or just a sheet of plywood. A properly built torsion box floor actually requires NO frame other than an axle connection and a tongue and there are a few here that have been built just that way.

I used parts from a badly molested HF trailer for Chubby and for the barn I used a donor 5x8 utility trailer. I have my eye on a buddies 4x9 wave runner all aluminum for a 4x9 ultra light weight I would like to build this spring. More pics are in my album

But this is my favorite , I think it is Planovets frame .

This thing is beautiful....

[KevinP]

Considering on how light some of these tralers are I'm going to be using a trailer that has a 2" x 2" angle iron frame which will make it pretty light w/o the axle, wheels, and tires. I just have to straighten the hound out of it.....

[fseider]

Thanks bobhenry and KevinP.

Guess another way to word it is I'm looking for objective information vs subjective, as well as a practical design. (I'm sure titanium is out, though my son does work at a titanium reclamation center. Hmmm...) I doubt this topic would get into any argument like religion or politcs (but they are fun ), as we are talking about established engineering principles here for the sake of safety and practicality, not just wild guesses (I would hope!). (OK, engineers will differ of course, but their differences typically are fairly meaningless and trivial to the average layman.) Experience and personal 'rule of thumb' are great and valuable, but they do tend to vary widely form person to person, and again, subjective, not objective. How else does an inspector know what a trailer should be rated for? While it's easy enough to find information on the various characteristics of virtually any single shape of a piece of steel of any type, it's the tying it all together to form a single unit where an engineer's expertiese comes into play.

All the plans I have seen so far appear to be for 2000/3500# units, with the distinction being around the axel, but the frame is the same between them otherwise. (Extra weight if you don't need 3500# capacity.) I can't seem to find anything around the 1500# range that doesn't also allow more load with a change of axles. In other words, handle the load without going overboard and adding additional weight.

The suggestion to look at a HF or TSC trailer makes good sense. A good starting point, if I can find one. I'll have to look a bit harder and perhaps do some traveling to measure.

The torsion axle comment - very good point, and that is my plan. I'm hoping the axle manufacture will provide some guideance there.

Thanks again,
Fred

[angib]

Right - here's the quick and dirty answer.

2"x2"x1/8" (or 11ga) square tube is enough for the main frame - the bit that sits under the teardrop body. You can add some crossmembers if you want, but they aren't really needed structurally. You can build lighter than this but you'll be working to save 10 or 20 pounds, so why bother?

However the tongue or A-frame is the bit that you need to get right. The best structural solution is an A-frame (one angled tongue member each side from coupler to main frame side rail) and the same 2"x2"x1/8" tube will do for up to 1500lb as long as the tongue/A-frame isn't longer than 48" - if you want it longer use 2"x2"x3/16" or 3"x2"x1/8" tube.

If you want a single tongue, then you need not only stronger tongue material, but a strong crossmember to fix it to. 3"x3"x1/8" tube would be a good choice for the tongue though that does mean finding a coupler to fit 3" tube. 3"x2"x3/16" would do vertically, but really could do with diagonal braces to be sure it won't shimmy sideways.

If using a single tongue, it must go to a second crossmember that is preferably 36" back from the front crossmember, and made of the same material as the main frame (eg, 2"x2"x1/8").

Andrew

[Carter]

Well Put Andrew

and BTW, 3" couplers are an off the shelf item here.

Jim

[fseider]

Thanks all for the replies! I'll be looking into using 2X2X1/8 and a bit larger for the tongue.

Thanks,
Fred