box section size

[Irishexplorer]

Hi all, I am about to start building a lightweight chassis under 500kg with suspension for road use. Locally I can acquire 50x50mm, or I think 60x30mm. which one of these is recommended for strength and weight. Are there any handy plans that I could review?

Thanks for your time in advance, Tristan.

[saywhatthat]

have you looked here https://web.archive.org/web/20151114223707/http://www.angib.pwp.blueyonder.co.uk/teardrop/tear00.htm

[tony.latham]

Are there any handy plans that I could review?

I think that 60x30 is a bit on the skinny side. (But I'm not an engineer.) I added a chassis design with material sizes on your other post.



Tony

[Irishexplorer]

What about if the a-frame and the outside of the chassis is 50x50 box section but the ribs are 50x50 angle? Would that give enough strength?

[tony.latham]

What about if the a-frame and the outside of the chassis is 50x50 box section but the ribs are 50x50 angle? Would that give enough strength?

Let's revisit my chassis plan.



That rear cross member (I think you are calling it a rib) is placed there primarily to support the weight of the water jug, battery and cooler in the galley. It's 50mm x 50mm 3mm thick angle.

The front cross member is square tubing because it's a structural member tying in the tongue (you call it the A-frame I think) to the frame.

The second cross member from the front is actually the torsion axles which acts as one. If I used a spring axle, I'd add another piece of angle there.

So yeah, 3mm angle is fine for the cross members except for the one above the tongue. That's what this non-engineer thinks.

Tony

[Irishexplorer]

That's great, thank you. I am also thinking of using 10' inch wheels, would that be adequate?

[tony.latham]

I am also thinking of using 10' inch wheels...

I run 15" wheels since I travel the backroads a lot. It just depends on your roads and chuck holes. But also, the bigger the diameter the slower it revolves around the bearing.



Tony

[Irishexplorer]

So I have found a 6.9ft x 4ft trailer for sale. It's 50mm x 50mm box section and it has leaf springs and i think 14' wheels and it looks to be galvanised steel. I'm curious as to what you think of this before buying it to start my project

thanks a million, Tristan

[saltydawg]

Well its 2x2 in american numbers so thats a good generic tube size, But I would make sure its .120 inches thick. Do you know the spring rate?

A 6.9 bu 4 is a strange size for trailers here, but it is stretchable to a 8 by 5 with out too much issues if you dont mind the wheels tucked inside the side of the cabin. Basically add 6 inches on every side. We need pics??? If your going off road at all you might want to think about flipping the axle on top of the springs to get a little more clearance and cut down on how much the wheel wells stick up in the cabin.

[swoody126]

That's great, thank you. I am also thinking of using 10' inch wheels, would that be adequate?

IMHO 10" wheels would carry the weight and work well enuff on paved roads

the real issue for me would be tire availability for replacing them on the road/a trip

10" trailer tire/wheel combinations have given way to 12" & 13" units and when perusing the shelves @ places like Tractor Supply Northern Tool Lowes and even Horror Fright i don't see the 10" units

check your local outlets for avaiability

having had trailer tire issues on the road in the past i now choose to only tire my trailers(of all kinds) w/ units that are universally available

side note... i did find out that the coal mining industry uses 8" trailer tires to support their conveyor belts for moving product within the mines as well as above ground and mine supply businesses carry them in large numbers ;-)

even having a spare wont cover all bases

getting stranded between noon on a Saturday and Monday morning when the stores/businesses open back up can be a real PITA

just this old man's 2¢ worth

sw

[Irishexplorer]

so i bought the trailer because i thought that if it doesn't work it would still be a good investment to earn some extra money for my teardrop. it is made up of 50mm x 50mm box section and i think it is 2 or 3mm thick. it also has 15' inch wheels and 3 leaf springs and a a steel floor. it is galvanised steel.
i have pictures of it but i don't know how to post them up

[saltydawg]

so i bought the trailer because i thought that if it doesn't work it would still be a good investment to earn some extra money for my teardrop. it is made up of 50mm x 50mm box section and i think it is 2 or 3mm thick. it also has 15' inch wheels and 3 leaf springs and a a steel floor. it is galvanised steel.
i have pictures of it but i don't know how to post them up

a couple of options for pictures see below, if you have a bunch of trouble message me with a email address and you can email them to me.

viewtopic.php?f=2&t=73119

[Irishexplorer]

hopefully this link will work. it shows some pictures i took of the trailer. i will try and get some better ones taken and uploaded later in the week.
https://imgur.com/a/vcjomCp
thanks a million, Tristan

[saltydawg]

Yes the pics worked.

Interesting design, you really need to add a center leg to the tongue that goes back about 20% of the deck length. That tongue as it is, is not very strong. I would take the coupler off, cut a 2 inch gap and cut a 2 inch gap in the lower tube of the front of the deck and weld in the center leg.

Also if your going to extend the deck forward that would really help with the tongue as well sense it would give a second weld point that the A frame is welded too. Now the good thing is when you add a center leg you can make up the tongue length lost to extending the deck.

[tony.latham]

hopefully this link will work.

I just wanna know who built the retaining wall.

Tony