Modify On-Road Standard Trailer to Off-Road

Hi there!! The main problem is the normal trailer is lightly built. Areas where new heavy springs are mounted would need to be strengthened, a frame replaced and a new axle, braked or unbraked depending on you weight and use.. Usually it would not be viable to convert. New suspension could cost upwards of $1000 for electric braked setup or $600 odd for an unbraked axle, hubs and springs and then i guess you would need beter rims and tyres... Regards Michael

Jeff,

I used to think my 7x 4 box trailer was well built. I was actually designing a camper to build and mount on that trailer for camping trips in the bush when I came across a much better camper and eventually bought it.

The difference between the genuine 4x4 trailer that is my camper and my box trailer is staggering. There is no way that I could modify the box trailer to match the strength of the camper.

My box trailer has a pretty good chassis made out of medium weight angle iron, the camper is 45 mm box section. The box trailer has 3 east-west frame members the camper has 5 running north south.

The box trailer has had problems with the leaf spring mounting brackets tearing out of the frame, the camper has not had any such problem. The box trailer has had the A frame tear away from the body the camper has not had any such problem.

The max load in the box trailer has been just under 1000kg on the odd occasion. The camper regularly carries 1100kg . The box trailer has done very little off road work, the camper has done over 35,000km in outback and off-road conditions, including sand dunes, river crossings, dry creek beds and mountain fire trails.

My camper is made of sheet metal that is probably double the weight of that used in the box trailer. Everything about the camper is stronger and heavier than on the box trailer. Even the mudguards are designed to provide stiffness to the side of the camper trailer rather than just being tacked on.

I think you would be much better off to invest in a purpose built off road trailer. I could show you photos of a really well built but badly damaged box trailer I passed out near Lake Eyre years ago. The guy who owned it spent nearly $3000.00 and most of his holiday recovering this trailer. At the time that would have bought him a pretty good off road trailer.

In my opinion you would be much better off to buy a properly built and tested camper.

By the way I have been towing trailers off road for 17 years.

Duncs

You can do it and you "can" save heaps .... but ........ you can only do it if you have the gear and skills required ....
No 1 would be to be a good welder, not average but MUST be good and if you are you will already have a welder and stuff to do that part and being a welder you will know exactly what parts you will need to modify .......
You may get away with "mates" but i would NOT go there, they may be good but you will be towing it and when it snaps in half out back of pucknowswhere then you will be in big trouble, ask on this forum as to how many trailers are simply left to rot in the outback and you will then see why ......
I hope you can do it as the simple answer is "yes" and you can build to custom made to suit you .... but....
Cheers
Plus i may add, check out e bay and the likes, there are heaps of very good and cheap s/h off road trailers on it

Joe

If you are "handy" enough to do the mods required, you could build a new off road trailer from scratch and sell the old one.

Cheers,
Peter
OKA196 Motorhome

G'day Jeff, I beefed up my 7x5 garden variety trailer to do the Savannah way 2 years ago, I added 50x50 from coupling to rear, and several more of the same where I thought were required(flipped trailer over to do all mods) replaced hubs to six stud, 16" wheels, under slung axle, re-welded every weld - but I did not up-grade standard slipper springs?????????????.
You can guess that structurally the trailer was fine but snapped R/H springs 50 ks from Burketown.
So yes it can be done but do it all - coz what you think will be OK will be the bit that fails.
Give it a shot - Good luck

I would suggest, as others have, that you buy a purpose built trailer & add your
top. Firstly, if you get a 7 by 4 your options for tops are better & larger sizes
are available. I did this about 5 years ago & the total "on road" cost was less than
$5k. 40k later we have had no issues with trailer or tent. Top is Chinese Oztrail,
trailer sourced in Sydney. Let me know if you require location......oldbaz.

As others have said, it can be done, but you will need the following : welding skills, time, money, patience, and a design to build to. Don't start the project without knowing what you what the finished product to be, otherwise it will better to purchase one.
I modified a standard trailer for off-road use a couple of years ago and was very happy with the end result. The major issue is the chassis. To avoid problems, I didn't stuff about trying to strengthen it, I replaced it. I cut the box off and made a new chassis, front to back, with 75x150. I was lucky enough to have a friend's factor with the gear to bend it to shape without the need to cut and weld. This makes a very strong chassis. After gusseting it and fitting off-road suspension and running gear, if was as strong as a tank. I refitted the original box, but strengthened it by running full welds and re-enforcing.
The end result was good, a very strong off-road trailer that is still going well today with it's new owner. It's probably been been around Australia twice already. If you don't take into accound the cost of you own labour, it's worth doing.
Capt.

Hi Jeff
It all depends on your trailer as it is now, how much weight you will want to carry and the roads you intend to tow it on. You have mentioned dirt roads, if this is all it is and your trailer is not just a cheap piece of junk then you can usually get away with easy cheap modifications.
In the past I have just re-welded and added more welds where needed and replaced the drawbar with a longer 'A' frame that weld to the front spring hangers. I would not even bother replacing the springs or axle unless you are going to carry excess weight.
Chris

Hi JFRCN,
All posts have valid points. It can be done and depending on your requirements can be a small or large task. If you want it for going down dirt tracks or to the beach then its a good project to do. A trailer is no difference to the 4x4 you can have a "Off road weapon or the daily driver"
Cut off and replace A frame using a off road hitch, make it out of 75x50x3 "Dura Gal" (due to the coating process the tensile strength is better than painted tube) make it longer and take it right back to the springs. Fit new spring hangers utilizing a heavy piece of RHS then run a transverse tube to lock it in (stops the tube from tripping). By doing this you can also lift the hight of the trailer to level it out behind your car. I have done this several times for family and takes me about 5 hrs. (I'm a boilermaker by trade)
As stated by others if your intent is to do the Simpson or CSR. Buy a trailer to suit.

Cheers Craig

HI all

Thanks getting some good advice here - my welding skills are average and seems like many hassels with regards to modifying a standard trailer to 4 x 4. So my best 'budget' option is look at purchasing a purpose made 4 x 4 off road trailer (say 7 x 4 foot) and then looking at tent trailer to attach?

I do want it to be reliable !!

Not sure if you can help but where is best place to look for off road trailers only (ie manufacturers or ebay) ?

Secondly there is obviously a lot of differecne between on-road and off-road trailers but is there any accepted standards that defines the differecne. I assume many trailers fit somewhere between on a sliding scale.

Is there actually any agreed specification which defines or classifies a trailer as 'off-road' as opopsed to 'on-road' and do manufacturers adhere to these specs. Any thoughts or advice where I could get further info much appreciate

much thanks

Jeff