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Franklin
16th Oct 2009, 11:20 PM
G'day,
I bought this unfinished trailer and are planning on the following mods.

1). Extending the tray by 0.5m, which will put the wheels in about the centre (slightly front wards) of the tray. Shouldn't be a problem as the drawbar is long and will have a couple of spares mounted on it.

2) It has an independent suspension arrangement, and I was wondering if the spring hangers should be vertical or not?

3). Replace the drawbaw with 75x50x4 RHS, currently its 50x50x2 RHS and I think it looks too weak..

and yes the intention is to hot dip galvanise it when I've finished welding.

unfortunately the axles have no brake capability, Is it difficult to add this as I will be limited to 750kg aggregate mass without brakes.

thanks
frank

jatt
19th Oct 2009, 06:50 AM
Extending the tray by 0.5m

What are u using the trailer for? Is it a camper? Seeing the jerry holders on the side. Asking cause I recon it would be a pain extending the tray, especially by the time u muck around with the sides, floor etc.. A toolbox on the front perhaps....


Replace the drawbaw with 75x50x4 RHS

Unless u are carrying heaps of weight a 4 mm wall thickness.... The way I look at it is, its all added weight to the trailer at the end of the day. Maybe step it down to 3.


unfortunately the axles have no brake capability, Is it difficult to add this as I will be limited to 750kg aggregate mass without brakes.


Whichever system is used: disc, electric, hydraulic, then one needs to replace the hubs.

Electric brakes are easier at the trailer end - two wires to connect once the hubs are fitted, but of course one needs a controller in the car, wiring it in at the car end etc..


Hydraulic, elec over hydraulic: the fun of running brake lines on the trailer. Of course u would need flexible lines to the hubs as per a car.

Have fun.

dazzler
19th Oct 2009, 08:29 PM
Hi Franklin

I would unbolt the "independent" parts and throw them away. The leaf springs are fighting against the arc of the independent arm.

Replace with a 45mm square axle.

75x50x3mm is fine. 4mm is overkill. My plant trailers that carry over 2t only have 3mm.

Have fun!

Franklin
19th Oct 2009, 09:18 PM
jatt,
main reason for extending is to fit my 8' dinghy in it, plan to use it camping and add a camper frame over the trailer (above the boat). But thats stage 2.

already have a length of 75x50x4. so will probably use it.

think I'll leave brakes until I have some idea of what its going to weight.

dazzler
the springs have shackles both ends, so should be free to follow the arc of the trailing arm. Might use a clamp and pull the axle onto the frame just to check.
If I was going to add a shock absorber, where would I put it?

thumpergman
19th Oct 2009, 10:14 PM
gday mate your draw bar is plenty strong enough dont spend any time changing it

from what you stated you should not realy need brakes so i wouldnt bother with that now

can you extend the body towards the front instead of adding on the back?

dazzler
19th Oct 2009, 10:58 PM
An interesting suspension. Great idea to check with the clamp. Dont forget to tell us how it goes as its got me intrigued.

Franklin
20th Oct 2009, 12:38 PM
I could extend the body towards the front. except I've just finished making the front tailgate hinge, and if i extended the front the wheels would be way towards the back of the trailer, whereas if i extend the rear the wheels will be close to central (of the tray).

checked the suspension, not good, the rear hanger is placed wrongly, more grinding and welding :(.

Holes in chassis rail are so I could drill interal holes in rail where it meets the cross beams, to allow galvanising to flow. These should have been done when built, but you get that with buying unfinished projects. Will plate these external holes with a diamond plate.

Franklin
20th Oct 2009, 01:07 PM
right now I'm wondering what air bag suspension would cost and how difficult it is to fit?

thumpergman
20th Oct 2009, 05:46 PM
you need to ask yourself how much wait you are carying before bothering going to that expence im sure a 8 foot boat would not way much

if i was you i would go down to a trailer dealer and see how they are built you will be suprised how basic they are for the amount of wait they are designed to carry

mabey take a couple of photos of the suspension with you to the dealer and ask a few questions

ive given no imput here becuase ive never seen the set up you have

jatt
20th Oct 2009, 06:38 PM
Could a frame (ladder rack) of sorts be welded to the drawbar to carry the front of the dingy?

All I can say about suspension setups is keep it simple. Admit I'm a fan of the basic leaf spring design. If u break something out in woop woop its easier to rig something up to get u home. I know airbags for 4wds are quite expensive, so can only assume ones to suit ur application will be olong similar lines. Never fitted em to a trailer.

Another possible idea for brakes (if u decide to go down that route later) is discs with a cable pull. From memory some boat trailers use em.

thumpergman's suggestion of going to a trailer joint and picking their brains is a good one.

dazzler
20th Oct 2009, 06:58 PM
ive given no imput here becuase ive never seen the set up you have

Hey that never stops me :p

Franklin
20th Oct 2009, 10:46 PM
Well I cut the rear shackle mount off and will shift it rearwards so that the shackle is vertical, that will give full movement to axle. Had to make a drift to remove the plastic bush from the shackle mount. Can't weld it or galvanise it with them in there. Could be difficult getting them back in after galvanising. Had to really belt it to get it out. Probably should have cut the mount off then put it in the press to get it out. Can try that on the other side one.

Almost started on extending the tray to the front (as per thumpergman's suggestion) and keeping the existing drawbar. but then noticed that the RHS I had laid on the drawbar didn't line up with the tray, out with the straight edge, and then a laser (just to double check). Sure enought the drawbar is already bent where it meets the tray (see photo).
50x50x2 RHS is definitely too small for a drawbar (the trailer hasn't even had a load in it yet), so will be cutting the A-frame off and making one up out of the 75x50x4 RHS I have. I think I will make it pivot where it attaches to the trailer frame (as per suggestion in Yonnee's thread), I've always wanted a tipping trailer. Still not sure which end to extend the tray on. But I'm pretty sure it's going to be the rear. Will make up the extension and see which end it looks better on.

thumpergman
22nd Oct 2009, 10:59 PM
who ever built it then must of been a bodgie bugger then dam make sure you have a good look over the trailer

this is my motor bike trailer its licenced to carry 750 kilos its completly bult out of 50x50 and i mainly used it off road never had a ploblem


did you ask a dealer about your suspension set up dude

Foo
24th Oct 2009, 08:09 PM
right now I'm wondering what air bag suspension would cost and how difficult it is to fit?
I think you would be looking at minimum $400 and that's going by 4wd costs:)

Franklin
25th Oct 2009, 04:14 AM
Well I ended up scrapping the trailer.
After pulling the A frame off I noticed that one of the main rails was built out of RHS that had been joined, and the last section of the A frame itself was comprised of three pieces of RHS joined. BTW the thickness of the A frame is 3mm not 2mm, the main rails are 2mm. So after seeing this dodgyness I knew I would not be happy with continuing. I think this was the correct decision for me as when dismantling I found some welds that weren't.

thumpergman
I apologise for my arrogance in stating that 50x50 is not suitable for a drawbar, I should have clarafied this with respect to drawbar length etc, but definitely not suitable for my drawbar. Just for reference my drawbar was 1700 from front of trailer to hitch point. Your trailer would appear to be more balanced with its load and with a shorter drawbar (and nicely built too) than the way this one was configured.

I will call an end to this thread and maybe start another when/if I end up building another trailer. I am keeping the suspension arrangement and sides and floor sheeting so I may build one up when I finish designing and costing it.

They say you learn more from mistakes than successes.

cheers
Frank

thumpergman
25th Oct 2009, 08:36 PM
sorry to here that frank i hope you didn't have to much money in it

it certainly better to be safe than to carry on with this project I'm glad you can still use some off it tho
cheers good luck on plan b :2tsup:

Fossil
28th Oct 2009, 10:39 AM
I think you have made the right choice. I also think you may have been constantly chasing your tail, trying to get it right, and then end up with a trailer that you weren't happy with.

The suspension is a copy of the Cruisemaster system. I have seen them before on off road trailers, and was considering making the same for mine, a few years back. I ended up getting a 2000kg rubber axle for $50.00 so went with that. The rubber axles are fantastic, on or off road IMO. Pics below FYI.

Here is a link to Cruisemaster Vehicle Components - trailer parts suspension winches brakes axles (http://www.vehiclecomponents.com.au/content/contentDetails.asp?ContentID=464)

Fossil
28th Oct 2009, 11:01 AM
And..... here is a link to airbag independent suspension that some guy in the States set up. It looks pretty good to me. "http://www.expeditionportal.com/forum/showthread.php?t=30442" as well as another link with pics of several styles of independent suspension. http://www.candm.com.au/archive_tom/108.php

Good luck with the project. :)

Franklin
28th Oct 2009, 11:44 AM
Fossil,
thanks for those links,
Mine is definitely a copy of the cruisemaster, almost identical, the bumpstop is a good idea, except I think I will put mine on the chassis rail, not on the axle.
yes am planning on reusing the sides, and hopefully the suspension arms, springs and axles (but I would like to add brakes).
I had a car trailer (single axle) with the torsion suspension, love those units. they tow nice and ride nice.

Air bag would be nice, but the springs are already there so i think I will stick with them. Interesting reading on the links, thanks again.

Am starting the design of plan B, will post when I think I've got it pretty firm and get some other options/opinions/advice.
cheers
Frank

dazzler
6th Nov 2009, 09:48 PM
thumpergman
I apologise for my arrogance in stating that 50x50 is not suitable for a drawbar, I should have clarafied this with respect to drawbar length etc, but definitely not suitable for my drawbar.

I dont think you need to apologise, its your view and your entitled to it, just as anyone is. I use 75 x 50 as a minimum with my std trailers and havent had an issue so stick with it.

Looking forward to the new trailer :2tsup:

Have you downloaded sketchup yet?. It is a really useful tool for estimating quantities/lengths etc!