Trailer Build

[omph]

Hi All,

I want to design and build a trailer but am wondering what the frame should be made of. It will be moving around the roads on occasion - think once a year or so. I could build the framework out of wood, seal it with marine varnish, ventilation to prevent mould/damp/rot etc but I am not so sure about its strength. The alternative is to build it out of steel, with which I have little experience. Any thoughts ?

Are there any guides out there for design/load/centre of gravity etc ?

 

[Burnerman]

I guess it all depends on the weight you intend to carry.......steel angle for me, and including steel tubing for the upper works. Consider copying an existing design, and maybe using Indespention suspension units. You may of course be able to recondition a second hand trailer from Gumtree or whatever.
John

 

[cdbe]

I think you need an IVA certificate for a self build trailer. Better buying one. If it needs modifying something older (pre 2012).

 

[Mottie]

I think you need an IVA certificate for a self build trailer. Better buying one. If it needs modifying something older (pre 2012).

Times must have changed. In the early 70’s when I was in my teens, I was into Anglia hot-Rod and banger racing. Quite a few of us on our estate were into it too. I, like others at the time, had my own cars that we prepared in the street - paid no more than a fiver for scrap cars in those days. Kept them in the garages underneath the tower blocks. We built our own trailers in those days, basically by bolting scaffold boards onto caravan chassis’. They used to bend like a banana when we had a zephyr 6 on them and we never bothered cutting off the outriggers. Once, on the way to a meeting in Harringay, we took a short cut down a side street and the outrigger caught the side of a car and opened it like a tin opener. It was an old Rolls Royce. I’ll never forget the registration number, it was TO R10. I’ve just checked and it on a Peugeot nowdays.

 

[Stivino]

A friend of mine had a caravan business. On a few occasions he would give me a scrap caravan, usually it would have been leaking with rotten wood, or had been blown over with the wind. I used to rip them to pieces and make a trailer out of it.
Maybe a visit to some caravan places will get you the basics for not a lot of money.

 

[norseman]

I concur with the answer from cdbe.

Times have indeed changed, though if you just knocked something up the chances of being 'pulled' are probably slight but if your creation caused an accident you could be in deep sh.. both with the law & your insurer.

 

[stevie888]

Steel every time.

Mine was made of 2inch steam barrel (pretty much scaffold tube), old bed irons for the corner posts, scaffold board bed and shutter ply sides. Hillman imp wheels, Moggie Minor leaf springs, an old cement mixer motor cover from a hedge bottom split to form mudmusic guards, electric cable a lump of temporary traffic light cable that a sweeper truck butcherd on site.

No brakes when first built as it was unladen weight that ruled, but when I eventually decided I ought to weigh the thing and it was a lot heavier than I thought so cobbled Hillman Imp back plates to the front hubs I'd used and an overrun coupling.

Pulled brilliantly because of the big wheels and the long drawbar. Used and abused for 45 years before SWMBO insisted we tidy the garden. Wish I'd been brave/foolish enough to refuse as could sure use it now at new place.

 

[Avocet]

The IVA requirement is an interesting one. It is absolutely correct that if you want to build a new trailer today, you need to get an IVA test done on it before you can legally put it on the road. The requirements aren't difficult. The Inspection manual is available here:

Individual Vehicle Approval (IVA) inspection manual: trailers

How trailers are inspected when they're being approved under the Individual Vehicle Approval (IVA) scheme to make sure they're safe to be used.

www.gov.uk

Domestic trailers tend to be category O1 (up to 750kg laden) or O2 (up to 3.5 tonnes laden).

However, the really silly thing in the UK is that there is no legal requirement for a trailer to be registered, so if you get pulled, there is no reliable way of knowing how old it is! I suspect there are lots of relatively new trailers around, which, as far as "Plod" is told, are actually old trailers that pre-date the requirement to have an approval test, but that someone has "restored"...

Leaving that aside, I've built plenty of trailers in the past. If it were me, I would:

1. Decide what maximum weight you want to tow and what size / type of objects. Do you want a car trailer? Box trailer? Boat trailer? Horsebox?

2. Check your towing vehicle and its maximum capacity. Most cars can tow up to a 500kg unbraked trailer. Some larger ones and vans, can tow up to 750kg unbraked.

Once you know this, you can select some suitable suspension, brakes, wheels and tyres and a towing hitch. Pretty much any trailer over 750kg laden, will need brakes, which bumps up the cost and complexity.

3. The design of the suspension will dictate your chassis material. It's not impossible to build one out of wood, but with something like an Indespension unit, the mounting points cover a very small footprint and I imagine it will be quite hard to safely feed the loads from that, into a wooden structure. Personally, I would go for steel, every time! However, I'm comfortable with welding. You don't HAVE to use Indespension (or one of the many copies of Indespension) available - I built my dad a trailer that used a salvaged Reliant axle and leaf springs, but Indespension-type units are very widely available.

4. Maybe look on some trailer parts websites to see what's available - places like Towsure, Trailer Tek, Autow Warehouse... there are dozens out there, where you can buy pretty much everything you need. Some places will sell you a complete, flat-packed trailer kit!

Flat Packed Car Trailers | Halfords UK

Explore flatbed and box trailers designed for UK roads. Easily transport luggage, equipment, or garden waste with reliable tow bar compatibility at Halfords.

www.halfords.com

https://www.ebay.co.uk/itm/194886775825?campid=5339147365&mkcid=1&mkevt=1&mkrid=710-53481-19255-0&toolid=20006&customid=CjwKCAjw2rrQBhBuEiwAarLWHT8CoZByFZaFSQF1kq99eTqCvc2fippjfycpjcy73bXZZIP3spdGGRoCKyMQAvD_BwE&loc_interest_ms=&loc_physical_ms=9045237&adtype=pla&gad_source=1&gad_campaignid=23840988194&gbraid=0AAAABDRoJI2n6vuXGgJgOd2AYzXtPkHwh&gclid=CjwKCAjw2rrQBhBuEiwAarLWHT8CoZByFZaFSQF1kq99eTqCvc2fippjfycpjcy73bXZZIP3spdGGRoCKyMQAvD_BwE

Maybe post back with what type, size and weight you're thinking of, and we could take the next step.