1" Box section too weak?

[webbaldo]

Ive been thinking about trailer designs for over a week now and its driving me mental lol

I want to make a trailer as light as possible. The HF trailer is out of the question here in the UK

Would a ladder style (bit like hf) made out of 1" box section be too weak? With a 50mm draw bar or A towing frame welded on?

Im just thinking 2inch box or angle would make the trailer too heavy?

Any advice or tutorials I havent found yet?

[bobhenry]

I had a home made truck rack for my 1 ton pickup made out of 1 inch square stock and had on several occasions hauled 1000 to 1400 pounds of lumber on it.



It was trussed in a manor such as I have drawn below. It makes a mini truss that places the top cords in tension to assist the flat bottom cord. I think this would work well for a teardrop. Allow the 2 short verticals to fall about where the mounting holes are on the axle mounting plate to help transfer the load to the top cord.

Pardon the rudimentary drawing

[webbaldo]

No that diagrams fine!, thanks for the image, some food for thought

[angib]

In my opinion, everything except the tongue/A-frame and the suspension cross-member (because you're in the UK, I assume you'll be using half axles), is just:
a) decoration;
b) something to hold up the floor until the walls are fitted;
c) reassurance for those who think they are building a small house.

A plywood teardrop body, on its own, is probably stronger than many of the frames put underneath it. What is needed is some framework to take the local loads at the suspension and the tongue/A-frame and spread those out into the body sides. That's why that is all my Ultralight chassis consists of - everything else is done by the body itself:



There's a local small trailer builder near me who uses 40x40x3 angle and 40x40x3 box for his frames (those are 1-5/8"x1-5/8"x1/8" in Merkan money):



I don't think the diagonals are a good idea, though they won't do any harm. His Tardis Trailers are worth a look.

[webbaldo]

Obivously i dont know much with trailers, but if I got pulled over in the UK with a bolt together lightweight as above, id get shot surely?

[angib]

I am just this week working on a spreadsheet to calculate tongue strength to meet the ISO standard that is used in the new British trailer IVA (Individual Vehicle Approval) test that comes into force from this October.

That Ultralight bolt-together chassis using 50x50x3 angle (same as 2"x2"x1/8") meets the ISO 7641 standard for a trailer weight up to 250kg (550 pounds) with a vertical front wall - or 220kg (485 pounds) with a sloped front wall, (because that increases the unsupported length of the tongue). 250kg is light but not unrealistic.

The strength can be increased by using 50x50x5 angle which raises the max weight to 420kg (920 pounds) or 360kg (790 pounds).

This does assume a well-constructed trailer body with glued joints, something like a boatbuilder would make. A few screws into the end grain of plywood wouldn't count.

Incidentally, most European caravans have bolted-on tongues.

[KCStudly]

In my opinion, everything except the tongue/A-frame and the suspension cross-member (because you're in the UK, I assume you'll be using half axles), is just:
a) decoration;
b) something to hold up the floor until the walls are fitted;
c) reassurance for those who think they are building a small house.

Add,
d) rock rails to keep the wood bits from turning to splinters when dragged through the rough and tumble of the great outdoors.

I do appreciate the notion that most over the road campers are probably overbuilt a tad, but sometimes there is a good reason to over build. There are exceptions to every rule; for example, traveling off road, or on rough back country roads.

Rocks, washed out gullies, and especially dropping onto a ledge would do a quick number on an unprotected ultra light box I have visions of thin plywood gouged open and spilling foam guts all over the trail, or a heavy galley sagging down, wall skins bulging after dropping hard onto a rock ledge right aft of the bulkhead. Oh sure, it would take a hard hit to do any real damage, and if built right you might just poke a small hole and have some scratches under the rear “bumper”, but when I'm hundreds of miles from the next human being, I need the confidence that steel provides, and I don’t want my dream trip to be soured by preventable damage.

Steel can be dragged over a lot of rocks before it starts having serious issues.

Label me a fat American with a gas guzzling SUV (two, actually). I’m not offended in the least. It’s true. I could build lighter, but there are no plans to attach wings, so…

To everything there is a purpose. When building light make sure you understand the purpose of each thing so you can make it just strong enough. When you are not sure what you will encounter, you have to make some allowances. That's all, really.

Peace.

[webbaldo]

Thanks for the advice!

[Forrest747]

1" should be fine. do a 2 inch tongue at least. I like angi setup although i wouldnt do it, i plan on some offroad and would like a little more steel under me. I did a 2 inch frame and with wheels and axle it came in at 400 pounds.

[webbaldo]

Thanks for all the advice, in the end I went with a 2x2 3mm thick box section frame with single bar tongue. It weighs in at about 45kg without axle/wheels (100lbs)