trailer designs/setups

Submitted: Monday, Jul 22, 2002 at 00:00
ThreadID: 1545 Views:8696 Replies:7 FollowUps:3
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auy budding trailer designers out there because i'm fishing for ideas for a tandem off road trailer.the basics are 7x5 tub tradesmans top single bar extendable draw bar both axles braked i'm looking at electric at this stage coil or leaf doesn't matter as long asits inderpendant .so if you have any good sites ideas and good suppliers throw your hat in the ring,most of what ive seen is over priced rubbish and this is to be a home project thanks johnsy
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Reply By: Allyn - Tuesday, Jul 23, 2002 at 00:00

Tuesday, Jul 23, 2002 at 00:00
suggest you look at 7x4 as 7x5 is too wide to stay in vehicle track. That would only need to be a single axle though. Definitely go for extended draw bar as that is the biggest fault with my OR Trailer. This is mainly due to swingaway wheel carrier on cruiser but all the same it's a problem with manouverability. Coil suspension is not worth the added expense for my money and is also difficult to repair roadside.
Due to time constraints I had a 7x4 Off Road Trailer purpose built (Extra Large Toolbox, 2x Jerry Holders, 2x Gas bottle holders, spare wheel carrier) fitted with new 16x8 mags, 450mm sides for under 2 grand.
Try for further ideas as it's a pretty informative web-site
AnswerID: 5054

Reply By: Robert - Tuesday, Jul 23, 2002 at 00:00

Tuesday, Jul 23, 2002 at 00:00
Hi Johnsy,

A site that may be of interest to you

Why a tandem trailer? another set of wheels is going to add a lot more weight , personally I think the lighter the trailer the better, a
heavy trailer isn't going to be much fun when trying to manoeuvre it by hand , also I wouldn't think a heavy trailer would be that practicable
if towing up steep tracks or going through mud etc if need be.
Also I can't see any real benefit in having independent apart from a softer ride which is mostly due to the coil springs not
the independent suspension, if you add coils to a live axle then your going to get the softer ride but you will loose out on the load
carrying ability of leaf springs , I assume if your talking tandem then your talking about carrying very heavy loads.
Why the extendable drawbar? - how are you going to keep it locked in place ? if you use a pull pins there will be movement
and if you bolt it then it will be time consuming to adjust.

I think a lot is not just over priced but also over engineered with no consideration at all to the weight factor etc. but that is probably
more to do with some people being more concerned about the macho look rather than practicality and it's cheaper for manufacturers
to make something out of thicker mild steel sections rather than using smaller lighter high grade steel.

Best thing about building it yourself - you will get exactly what you want and save a lot of money.
AnswerID: 5060

Follow Up By: Johnsy - Tuesday, Jul 23, 2002 at 00:00

Tuesday, Jul 23, 2002 at 00:00
thanks Allyn and Robert for your input iallready have a 6x4 which i put a full 75x50 1 piece a frame and chasis but its not braked and not safe .this is a idea of the load on my last trip tucker box two swags 4 chairs 15hp outboard 40 lts of h2o 40lts petrol for outboard and genset 20 lts diesel 2 camp ovens toolbox 2x70 lts clothes bins second spare for vehicle spare for trailer bucket of boat ropes anchor epirb life jackets topped of by a ship shape and the tinnie on top of that so its all getting a bit willing.thanks to the 4.2 td nissan flat torque curve it pulls fine.our idea generally is to base camp then explore an area for a few days so i dont really go rock hopping and trying the impossible with the trailer on although ive never had any trouble in sand driving up creeks and around sand hill country so i hope that explains where im coming from imreally tring to design a good stable dirt trailer with a bit more room. johnsy
FollowupID: 2167

Reply By: rodeoowner - Tuesday, Jul 23, 2002 at 00:00

Tuesday, Jul 23, 2002 at 00:00
A mate of mine bought a 7x4 single axle off road trailer a few months ago. It was one which usually came with the 'camper unit'. Cost him about $1300. Cheers.
AnswerID: 5083

Reply By: Tony- Thursday, Jul 25, 2002 at 00:00

Thursday, Jul 25, 2002 at 00:00
Johnsy, One thing I found with my o/r trailer after 10k travelling around rough corrugated desert tracks was that the leaf spring shackles and bushes and one hanger chewed out to buggery. It was fitted with off road trailer springs that were too 'heavy' for the job although they are the lightest of the 'off road springs'. I have now removed one leaf each and replaced the bushes with poly bushes instead of the hard nylon types. I'll see how this goes on our next trip. If I was starting from scratch I would fit greasable shackles off a 4x4 vehicle. This will mean you have to have the spring eyes re-rolled to match or have custom made springs or as others have done, use the springs off a 4x4 (maybe a susuki?). I beleive that having the trailer galvanised is worth its wieght in gold so to speak. I have a painted tool box on mine and although it does have a screen, some dirt/dust/stone/sand did sand blast the paint off parts off the tool box. The rest of the trailer is gal'd and shows no ill affects. Shockies did make a big difference to the trailer but alas, the mount points were not strong enough and one broke off. Make sure if you put shocks on, the mounting points are really strong. The fish plates that hold the springs to the axle need to provide protection to the U-bolt nuts also. Mine didn't and rocks/stone made such a mess of the threads and nuts that I had to use a grinder to take them off. Thats my experience, Cheers.
AnswerID: 5143

Reply By: johnsy - Friday, Jul 26, 2002 at 00:00

Friday, Jul 26, 2002 at 00:00
thanks Tony some really valid points.Ifeel that a spring pack out of falcon/holden wagon would be good then its only a matter of filling some 2oo ltr drums and playing with the rates on tracks to get it leaf is it.keep the ideas coming johnsy
AnswerID: 5160

Reply By: Yonnee - Sunday, Jul 28, 2002 at 00:00

Sunday, Jul 28, 2002 at 00:00
Having worked in the trailer game for a number of years, both as service/repairer and "one-off" custom builder, a couple of
things come to mind. First of all select the wheels that you'll be running, ideally the same size as your tow vehicle, and design
the chassis and track width to be the same as the tow vehicle. It usually makes for a slightly narrower trailer, but a godsend
if you're towing through soft ground. Second, single axle setups can be made with Falcon/Slimline/Set'E' & Set'F' bearings
which will give you a safe working load of 1450kg and Electric brakes with large diameter wheels are rated to about 1300kg
optimum braking capacity but will still work above this. Speaking of Electric brakes (this is my specialty), regardless of the
brand of brakes you end up buying, try and get Al-ko oval magnets with the 'o'-rings in them, even if you just buy them
as spares. They are interchangeable with Dexter ones, but don't wear out their mounting shaft anywhere near as much with
off-road vibrations. If you haven't chosen your brake controller yet, make sure you get the "motion sensing" type. There can
be major pitfalls with chosing the wrong one. Without risking repercsstions (I won't name names here), there are only two
decent controllers worth spending your money on. Some of the others can be downright dangerous. Leaf spring independent
is the way to go for suspension. Leaf spring because of its ease of replacement if damaged, and independent because of its
increased ground clearance at the middle of the trailer. O'briens/Orac couplings give you the most movement of all of the
couplings. Any others only give you between 22 and 25 degrees of movement from horizontal. Hope this helps, Yonnee.
AnswerID: 5200

Follow Up By: Skippyking - Sunday, Jul 28, 2002 at 00:00

Sunday, Jul 28, 2002 at 00:00
G'day Yonnee,

you seem reluctant to name which brake controllers are the good ones. Would you consider just naming the two you recommend, even though it would seem damning to the others. Thats what this forum is all about is exchanging info to help others.

I have an interest in fitting some trailer brakes in the future and would like to know your recommendation. If you don't want to do it on the forum would you be able to email me the ones you feel are the best.

Thanks for the good info you have already put forward.
FollowupID: 2222

Follow Up By: Yonnee - Wednesday, Jul 31, 2002 at 00:00

Wednesday, Jul 31, 2002 at 00:00
That would be "repercussions"! I can't spoll when it's late. :o)
OK, for those interested, the two controllers I recommend are either the Kelsey-Hayes or the Tekonsha Voyager, with the latter being my prefered choice. This being because the "gain" control (sets how much maximum power goes to the brakes) on the Tekonsha, also controls the maximum "emergency override" control, whereas with the Kelsey, the override always provides up to 100% power regardless of the gain setting. What this means is that when trying to set up your controller for maximum efficiency, in a short space of time you can use the override control to check and then adjust the gain control for maximum trailer braking without lock-up. With the Kelsey, it's a bit "hit and miss" till you adjust the gain correctly. Having used most, and fitted controllers for a living, I believe that these are the two best controllers available.
FollowupID: 2274

Reply By: Phil - Friday, Aug 09, 2002 at 00:00

Friday, Aug 09, 2002 at 00:00
Firstly I think you should update your 4x4. To pull a 7x5 trailer you need somthing a bit stronger and tougher that what you have. You know that your current 4x4 could not pull the skin off a rice puddiing.

AnswerID: 5546

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