Another trailer leaf spring thread

[PCRman]

Hi all.

I'm looking at getting a small camping trailer built before a road trip to Katherine later in the year. Usage will be mostly sealed Hwy and gravel road but I'll want something what will do medium sort of grade 4wd'ing and beaches. A pro will be building the Frame and box and I will be supplying the custom bits as well as doing the wiring and lights. Having done some research on trailer design and looked around at available parts I'm a little nonplussed about off the shelf trailer suspension and want to go for a more automotive setup (good springs, proper shackles, proper pins instead of threaded bolts etc).

My design specs for the trailer are;

Construction method, drawbar size, Axle location etc will be set by the trailer builder to give good strength and the usual 10% ball weight.
Weight will be kept to what is legal for my vit which I understand to be 450kg unbraked or 680kg unbraked. I don’t know if its optimistic but I'd like to keep the tare under 400kg.
Box size = 4.5' X 3.5' X 1.5' (LxWxH) although this may float around by 0.5' if it makes life easier.
Axle probably 40mm square although this may go up if needed.
Hubs will be F100 pattern disc brake hubs.
Hitch will be a Treeg/trigg style coupling with Hyd brakes and override.

Axle length will be chosen so that with the hubs on the hub face to hub face measurement will be as close to 1500mm as possible. With stock Vit rims on that should give me the same track width as the Vit and I'll run either 225/75R15, 215R15, or 215/80R15 so that I can have interchangeable tyres all round.

Suspension will be double eye springs with normal shackles (greaseable)
Bump stops and shocks will be a consideration after the bulk of the work is done so that weight and flex can be known and be used to make a sensible choice.

My biggest conundrum is spring selection.

I want to use a tapered spring with 3 or 4 leaves. Given the small size of the trailer I'd reckon I wont be able to go over 1m spring length (eye to eye unloaded so say 1.1-1.2m flat). Given the low weight of the set up 45mm springs will be the go and I'll use good quality automotive shackles, pins and bushes.

So...

What sort or spring and load rates should I be looking at to get a setup that will be manageable when empty (rare event and I could lower the tyre pressure anyway) and will tow well when full and not shake the . out of the contents. If I say that when empty I want 1" deflection and if the trailer tares at 400kg then I'll need ~880lb/" rate springs. But after that when I load up I'll want the rate to be progressively higher wont I? Any advise on approximate spring specs would be great then I can take that to a suspension place and find out what automotive springs meet those specs

Cheers

[nerida67]

dunno about spring rates on little trailers because ive got rolla roka (load sharing )springs on my trailer
in queensland u dont need brakes at all on any trailer that has a total weight upto 750 kgs, dunno if the same where u live
dont need break aways couplings if under 2 tonne loaded
non tappered wheels bearings would be over kill on your trailer
just normal taperred bearings would be ok ,not sure with the wheels(stud pattern) you want to run on the trailer of course
any trailer manufacturer will tell u wat springs to run,after all its not a large trailer

[PCRman]

Cheers for that. I'd not considered bearing type so I'll keep that in mind.

We have the same 750kg max in WA for trailers in general but it has an 'unless otherwise specified by the towing vehicle manufacturer' type statement added, which I think drops me to the miserly restrictions suzuki place on my vit. Of course having a copper pull me over who knows what the max towing weights for suzuki vitara's are is slim but better safe than sorry.

I'll definatly see what the trailer builder says about ideal springs. I'll be doing the Gibb river road and Sandstone to Southern Cross tracks on the WA section of my trip si I want to make sure I get a setup that wont fly apart on endless corrugations

Edit. On the coupling front, I've always prefered the override ones as it has the lever so that I can handbrake the trailer on a incline if needed but I'll give some thought to whether I should just go the generic Hyd brake trigg unit.

[nerida67]

most trailer axles have the bearing taper machined on axle,if you want straight non tappered bearings you would have to order it that way
even axles on my trailer are tapered and its a 2 tonne trailer,but tandem of course
the fuz around here are nailing people with trailers with those 1,000 litre water tanks on them,because they are over loaded
if goin to remote areas id be using parts ect that are fairly common,just in case u have any dramas

[PCRman]

if goin to remote areas id be using parts ect that are fairly common,just in case u have any dramas

Yeah, I'm hoping to find automotive springs and shackles that are suitable from something like a hilux, dunnydoor or falcon. Of couse I'll probably carry spare shackles and bearings anyway. Then I just have to worry about the springs (a few meters of fencing wire will go in just in case)

[Tiny]

if goin to remote areas id be using parts ect that are fairly common,just in case u have any dramas

Yeah, I'm hoping to find automotive springs and shackles that are suitable from something like a hilux, dunnydoor or falcon. Of couse I'll probably carry spare shackles and bearings anyway. Then I just have to worry about the springs (a few meters of fencing wire will go in just in case)

have you looked at a coil option? you may be able to use an IRS trailing arm set up off the rear of a FWD car

[Shadow]

most trailer axles have the bearing taper machined on axle,if you want straight non tappered bearings you would have to order it that way
even axles on my trailer are tapered and its a 2 tonne trailer,but tandem of course
the fuz around here are nailing people with trailers with those 1,000 litre water tanks on them,because they are over loaded
if goin to remote areas id be using parts ect that are fairly common,just in case u have any dramas

the taper is in the hub and is not machined into anything, the outer race of the bearing comes with the tapered roller bearing, and you press this into your hub.

The axle is machined to suit a standard tapered roller bearing setup, usually a holden (HQ etc) or FORD pattern.

I have yet to see a trailer axle that doesnt use tapered roller bearings.

[DamTriton]

if goin to remote areas id be using parts ect that are fairly common,just in case u have any dramas

Yeah, I'm hoping to find automotive springs and shackles that are suitable from something like a hilux, dunnydoor or falcon. Of couse I'll probably carry spare shackles and bearings anyway. Then I just have to worry about the springs (a few meters of fencing wire will go in just in case)

have you looked at a coil option? you may be able to use an IRS trailing arm set up off the rear of a FWD car

Early Subies had a neat setup. Semitrailing arms and transverse torsion bar suspension with an adjusting bolt/lever in the center of the torsion bar that allowed changes in ride height (or to maintain load height with added weight). Instant on-road/off-road conversion.

PS. Go electric brakes. Much easier when it comes to reversing the trailer if you find yourself offroad, rather than jumping out of the vehicle every 5 mins to engage/disengage the hydraulic override, especially if you are on your own.

[doe]

I run cruiser front leaves on boat motor bike and camping trailer just add or remove leaves as per wait of trailer. I have also built camper trailer for oll mate with hilux springs. Reason i run cruiser gear i have one all parts intchangeable same for oll mate with hilux springs. The longer the spring the better the ride then add shockes even better again. Done lots off corrugations towing boat to places it should not have gone the only problem ive had is stones destroying shocks.

[nerida67]

shadow,
i hear you
have been told when i replace my bearings to upgrade to a 4 wheel vechicle type bearing ,and get rid of the holden type bearing
have been told these type of bearings handle the load a bit better

and you say they are pressed in to hub,well maybe the new hubs and bearings i bought then are wrong because they were not pressed into anything,(unless u call adding grease being pressed that is ??)

[PCRman]

Early Subies had a neat setup. Semitrailing arms and transverse torsion bar suspension with an adjusting bolt/lever in the center of the torsion bar that allowed changes in ride height (or to maintain load height with added weight). Instant on-road/off-road conversion.

Any particular models?

PS. Go electric brakes. Much easier when it comes to reversing the trailer if you find yourself offroad, rather than jumping out of the vehicle every 5 mins to engage/disengage the hydraulic override, especially if you are on your own.

Thats a good point well made. I did not consider the idea but looking into it the electric hub/drum assembly is about the same cost as the Hyd disc assembly and the money I save on having a simpler hitch covers the cost of a controller and most of the wireing & materials for hook up. Do you use a pendulm style controller or a pure electric one?

[nerida67]

if the total weight of the loaded trailer is no more than 750 kgs
i wouldnt even bother with breaks at all
electric brakes run of a electric brake controller in your car, and brakes can be turned up or down to suit the requirements
ie turn up a bit when loaded and turn down when empty
would even bother with the expence if its only a little trailer

[PCRman]

Anyone know of a refrence guide that has the measurements/specs of common 4wd leaf springs?

[ludacris]

Give these guys a call.

http://www.vehiclecomponents.com.au/con ... tentID=466

They do a huge bearing axle setup and can answer any questions you have. They also supply greasable shackles and proper pins. Also go electric brakes for the extra safety. Nothing worse than not being able to stop and 750kg,s pushing you does put a huge load on your brakes.

Cris

[JimmyTheHuman]

Check out Melbourne Trailers, they custom made what you want and send it.

[DamTriton]

Early Subies had a neat setup. Semitrailing arms and transverse torsion bar suspension with an adjusting bolt/lever in the center of the torsion bar that allowed changes in ride height (or to maintain load height with added weight). Instant on-road/off-road conversion.

Any particular models? any late 70's/early 80's Leone 4WD wagon, possibly the 2WD sedans too.

PS. Go electric brakes. Much easier when it comes to reversing the trailer if you find yourself offroad, rather than jumping out of the vehicle every 5 mins to engage/disengage the hydraulic override, especially if you are on your own.

Thats a good point well made. I did not consider the idea but looking into it the electric hub/drum assembly is about the same cost as the Hyd disc assembly and the money I save on having a simpler hitch covers the cost of a controller and most of the wireing & materials for hook up. Do you use a pendulm style controller or a pure electric one? I personally don't use one, but have had said issues with trailers before when I was on my own, try it with a 2 tonne furniture trailer you can't see around

[PJ.zook]

Hey Jimmy, i assume you have to take the bikes on and off every time you want to use the trailer, or can you jsut swing em off the side?

How heavy is the Subaru swingarm setup? Would it be much more than a normal trailer axle and spring setup?

[JimmyTheHuman]

Bikes off. You could swing them off but i havent tried...i will ask my mate to try it on his, see how it goes

[DamTriton]

Hey Jimmy, i assume you have to take the bikes on and off every time you want to use the trailer, or can you jsut swing em off the side?

How heavy is the Subaru swingarm setup? Would it be much more than a normal trailer axle and spring setup?

Not sure of the weight of the setup but I think it would compare favourably to a light leaf setup. The real advantage is you could make the center a bit more adjustable with a hydraulic ram and lower the trailer for loading the bikes too.

[Surfin Alec]

I got a 7.5' x 4' high side box trailer, only a year old. Use it mainly for carting dirt bike and camping. Took it to Bendethera (3rd big camping trip loaded with about 200kgs of stuff) and on the way out I had 2 leafs of my 3 leaf spring pack snap and fall out in the middle of no where.

Managed to find the 2 halves eventually of the longer spring to make a dodgey 3 spring pack to get us home. Rang the trailer mob who made it and they tell me it should have a 5 spring pack, not a 3 and no warranty. (also found they used 1/2" bolts and all the holes, hangers and bushes that were meant for 9/16" bolts too.)

I dont think the off the shelf trailer spring are of the highest quality anyway. Seems good now after a rebuild but I wouldnt go for a 3 spring pack to go offroad and loaded in my opinion. Go the 4 minimum.

[JimmyTheHuman]

Yeah that sounds a bit light weight. I would always buy them from a proper trailer supply place too...not from any box mover type stores.

Mine has 8 or 9 leafs.

[ludacris]

Mine is 1600KG leafs fixed front greasable pin and greasable shackle rear. 2000kg electric brake axle with landcruiser stud pattern and big bearings. Quite offroad and drives awsome on road. Strong as too. Cost just over $1200.

The problem with the slipper spring set up is after 50km's of rough tracks you want to un hitch the thing and leave it because of the noise.

Pretty sure you can get the independent setup from the same mob for around the same dollars but not sure if that is with electric brakes and big bearings.

Cris