Trailer geometry

[Angusdog]

I'm looking to make a camping trailer. It won't be for off-road but it feels like a good project to make something stronger and more useful than an off-the-shelf jobbie.

I've knocked up a design and just wondering if the drawbar is long enough. I've been eyeballing trailer for a while and some seem to have massively long drawbars and I'm wondering if this makes them tow better. The ones in my plans below 'look' okay to me. They'd be 70x40mm. The rest is a mix of 40x40 and 25x25 RHS.

The pics below show my plan, the width of the load space is 1200mm. The idea is to build a slightly heavier 'base' trailer for general household duties, then drop a cage on it which has (a) a rack on the top for bikes, (b) a tarp around it for weather protection and possibly drop down side for cooking etc. I may build storage boxes in front and behind the wheels.

Home built trailers are legal in NZ incidentally. All feedback and criticism welcome.

 

[madkayaker]

the best idea i can make is go to a shop that sells proper made ones and measure theres. and while your there also consider the cost/ time benefit of getting a ready made one. every time i have costed up building a trailer it has been cheeper to get a ready made unit instead of the bits to make it.

 

[zzr1200]

I'd be inclined to either move the axle back about 4 or 5 inches or extend the load area forward 4 or 5 inches to give some natural nose weight in the design.

Also the load capacity of the trailer affects the materials you use and the length of the "A" Frame, plus the tow vehicle can also effect the design spec's.

Your chassis design just seems a bit square for a normal chassis to me...

 

[Keith 66]

If you are thinking of building a trailer from scratch be aware that virtually all trailers now have to have either type approval or pass an IVA test.
This link sums it up, http://www.armitagetrailers.com/trailerlaw.htm,
For many of it is going to be a pain, but if an old trailer is rebuilt you may be ok. At least one local trailer manufacter has been forced to shut own due to the increased costs.

 

[the snooper]

If you are thinking of building a trailer from scratch be aware that virtually all trailers now have to have either type approval or pass an IVA test.
This link sums it up, http://www.armitagetrailers.com/trailerlaw.htm,
For many of it is going to be a pain, but if an old trailer is rebuilt you may be ok. At least one local trailer manufacter has been forced to shut own due to the increased costs.

he's not in the uk

 

[W.olly]

I understand all these new laws on DIY trailer builds, but how the heck are the VOSA or who ever pulls you going to prove when the trailer was built, i think it will takes many years to get it really sorted.

And as stated the chap is no tin the UK, jammy sod.

I have made a few trailers and have always made it with a bit of hitch/nose weight, but not always you need to move the axle forward, the A frame and hith helps out there and any other additions.

For a trailer that size i would fit a A frame of around 42 inch.

wolly

 

[cumbriasteve]

A longer drawbar won't make towing easier but will make reversing slightly easier, short box trailers are very responsive to the slightest steering change so any additional length aids things a bit.

When I made box trailers the wheels were set back from centre of the box 100mm, the A frame then added the required nose weight to about the right weight.

Nose weight can of course be corrected easily when loading the trailer, can't remember the suggested ideal, it was years ago but 15kg comes to mind, using a spring balance hooked into the tow hitch.

Your design looks good, my only suggestion for added strength would be to extend the centre of the frame to the nose of the A, in effect having the A frame pulling from 3 points, not critical but I always liked a good solid chassis.

 

[madkayaker]

If you are thinking of building a trailer from scratch be aware that virtually all trailers now have to have either type approval or pass an IVA test.
This link sums it up, http://www.armitagetrailers.com/trailerlaw.htm,
For many of it is going to be a pain, but if an old trailer is rebuilt you may be ok. At least one local trailer manufacter has been forced to shut own due to the increased costs.

might be worth checking the OP's location

 

[the snooper]

might be worth checking the OP's location

might have been worth checking post 5

 

[Westfield-builder]

might have been worth checking post 5

Or post 1 !