Is independent suspension that much better than leaf spring?

[BSM]

I've been looking at camper trailers as many others on this forum. I've been looking at the Cub Spacematic Regal off-road. This is a 945kg camper with a ball weight of approx 100kg. This camper only comes with leaf spring suspension. To get the independent suspension (along with other kit) it's the next model up and an additional $8k.

We want to take the D3 and a hard floor camper from Melbourne to the Kimberly and travel Gibb River Rd and Tanami.

What do folks think about a leaf spring suspension trailer on those tracks? Are there any concerns, or is the D3s suspension likely to cause me problems before any camper trailers suspension will?

[Vern]

To answer your question, no!
I have had both leaf and independent cub campers, the leaf towed better on road, dirt tracks about the same, off road the independent was slightly better in particular to the slow stuff, but not $8k better

[TerryO]

If your worried about the D3's suspension and you have airbag then get one of Gordon's (GOE) air up kits, so you can pump each corner up independently, you will need a separate compressor but chances are you will have one for tyres etc.. Plus add in a diagnostic tool that also clears faults and you should have most everything that can go wrong covered.

[BSM]

If your worried about the D3's suspension and you have airbag then get one of Gordon's (GOE) air up kits, so you can pump each corner up independently, you will need a separate compressor but chances are you will have one for tyres etc.. Plus add in a diagnostic tool that also clears faults and you should have most everything that can go wrong covered.

Hi Terry, I've got a diagnostic tool, and I am aware of the GOE kit. It's more the thought of a shock absorber failing that I am referring to. There's a description on one here that's a little sobering. (http://www.aulro.com/afvb/l322-range-rover/199922-murphys-law-catastrophic-failure-very-bad-place.html)

[gusthedog]

I have owned a number of campers with independent, spring and Alko torsion bars. My t-van with independent was better everywhere (dirt, road and off road) compared to either spring or torsion bars sprung trailers. However, I'm not familiar with the cub independent setup and Vern could well be correct that the spring version in the cub range is better. If you step outside the cub brand however, this will not be the case generally in my experience.

[Graeme]

Those shocks are ecu-controlled variable rate that endeavour to maximise ride comfort and vehicle control which causes the rates to be adjusted to correct shock fade from excessive heat so don't give any warning of overheating. Just make sure your D3 shocks are in good condition, not on their last legs.

[JDNSW]

I think the answer to the original question has to be - it depends.

It all depends on the implementation. There are good and bad in both types. In theory, independent should be a little better.

John

[weeds]

not ever having independent but my observations are..........

independent may be/probably is better on dirt roads when travelling at speed

I don't see how independent is any better for slow rough stuff as all the pivoting is done at the tow hitch

on the black stuff, I don't see any advantage between the two

I think its offered as it the latest trend in suspension and buyer take up th eoption.....although in saying that if I build a new chassis for my camper than it will more than likely have independent air suspension, why, cause I can I suppose and it should match my electric over hydraulic brakes nicely.

[Redback]

I don't see the issue in trusting offroad leaf springs, never had an issue, in the 10yrs we've had our camper, only replaced our leafs about 3 years ago, pretty good considering where we go.

Over the years I've seen a lot of trailers with broken independent suspension, usually broken leaf sprung trailers is due to the age and not heavy enough for the weight of the trailer.

There's a lot of stress at one point in independent suspension and this is where they normally fail, where the spring, shock and arms meet, at the single point where the stub axle is, this is where I've seen most fail.

For them to be really strong they need to be very strong here and probably why they are very expensive, I wouldn't touch the AL-KO rubber independent thingies.

That's my experience, oh and I don't have shockies on my camper, some on here have followed us when towing at speed, no bounce, no sway, just sits behind the car nicely.

Knowing Cub, I'll garrentee they have either 7 or 8 or 9 leaf, AL-KO offroad rebound leaf springs, basically the best leaf springs on the market, which is what are on our camper.

Baz.

[weeds]

oh and I don't have shockies on my camper, some on here have followed us when towing at speed, no bounce, no sway, just sits behind the car nicely.

Baz.

what that's taboo isn't it.........

I have vehicle component leaf springs without shockies.......I always thought they were the best leafs around, 2nd best will do me

[Graeme]

I fitted VC long travel off-road leaf springs along with shocks to my 1990 van that had a harsh independent setup. I chose the top VC springs because they use less leaves for the same load carrying than the more popular brand as I considered they would provide a softer ride. The van will never see proper off-road conditions but hopefully will hold together longer over rougher gravel roads.

[simmo1]

Hi folks,

We have a campomatic with independent coils. Had it for a few years, and I think it was built maybe 1996, the first of them with coils. I think they used Alco rubber torsion before that.

I haven't taken it on rough bush roads but have driven on rough 'cobbly' bitumen, the type that in a 60 series cruiser gives young the s....ts. The camper rides as smooth as, on these roads whilst the towing vehicle does its stuff, bouncing along (Disco TD5, Subaru Forrester, Nissan X Trail). The camper would be the smoothest ride in these conditions. I have no idea how it would hold up on long distance rough outback roads though.

Cheers, Simmo

[David Hawes]

I don't know why you'd want to tow a trailer with independent suspension behind a truck with solid axles, and I know which I'd prefer to repair in the field:o But why doesn't someone make a solid axle with coil springs:confused:
Dave

[JDNSW]

I don't know why you'd want to tow a trailer with independent suspension behind a truck with solid axles, and I know which I'd prefer to repair in the field:o But why doesn't someone make a solid axle with coil springs:confused:
Dave

As pointed out in an earlier post - the principal drawback of coils is that they place the suspension load at a single point instead of two points. This means either a heavier or more complicated chassis design. I suggest this may explain it!

John

[Bundalene]

IMHO it is difficult to fit a decent set of coils under a camper, without either making the axle too low or lifting the camper too high.

We have had experience with trailers, both with a S1 Disco rear axle housing ends, one with leaf springs and shocks and the other (boat trailer) with the the suspension set-up of a Series1 Disco, coils, trailing arms, A frame and shocks, all at the same angles.

The boat trailer tows way better, both on rough terrain and corrugations, the ride is even much smoother than the tow vehicle, which is pretty good. Also, other than replacing the occasional shock, and regular greasing of wheel bearings, we haven't touched the suspension in about 150,000kms




https://www.aulro.com/afvb/images/imported/2014/12/93.jpg (https://imageshack.com/i/ipVLFe0Pj)


excuse the poor pic - very dusty and smoky from burning off
https://www.aulro.com/afvb/images/imported/2014/12/94.jpg (https://imageshack.com/i/eyfrEZJsj)




Erich

[gusthedog]

I don't know why you'd want to tow a trailer with independent suspension behind a truck with solid axles, and I know which I'd prefer to repair in the field:o But why doesn't someone make a solid axle with coil springs:confused:
Dave

You'd have to tow one to find out. I think the guys at Tvan who make trailers for the military know a thing or two about trailers and their setup is awesome. Try a properly set up independent set up off road and you'll know what I mean ;)

[Tank]

2 major problems with independent axles on trailers, or anything really is that the more load you put on the lower your centre clearance becomes. In theory you could load an ind. Susp. (IS) to the point where the centre underneath is actually sitting on the ground.
Also when under load and an axle (wheel) travels upwards (over a rock, say), the pivot point of that IS axle travels in an opposite direction. Laws of Physics For every action there is an equal and opposite REACTION.
A straight beam axle with leaf springs will ALWAYS have the same ground clearance, C/L of axle stub to ground, depending on the height of the tyre and wheel, also less pivoting parts and a bush leaf spring ain't hard to rig, try repairing a snapped pivot point on IS in the scrub, Regards Frank.

[PhilipA]

2 major problems with independent axles on trailers, or anything really is that the more load you put on the lower your centre clearance becomes


All independent suspension camper trailers ( I have seen) have much MORE ground clearance than leaf sprung trailers. Also because they are camper trailers the suspension is usually pretty stiff so that people can walk around in them. The lowest point on mine by far is the spare wheel underneath, and it can only be where it is because it is independent.

The main benefit of independent , in my Camp'o'matic anyway is no skipping on corners at all, and no skipping on corrugations at all.
Mine is over engineered with parallel bearings with a load rating of 1500KG.
While there are more solid axle campers out there I have only ever seen failed solid axle campers never independent , maybe because there are many more failure points on a solid axle in spring centre bolts, u bolts, and shackle welds to frame. Shackle weld failure is the most common failure point according to the Coen RACQ recovery bloke, and he knows!

It is far easier to under specify a solid axle than an independent, as the parts are easily obtainable from any trailer parts supplier, so dodgy builders build to a price, while independent is usually part of a complete chassis and sold as part of an upmarket model.

I only once saw a photo in a 4WD magazine of a Camp'o'matic being limped home on a piece of timber on one side, and I thought how could that happen, and the answer must have been total neglect, as the parallel bearing must have seized so tight it ripped off the stub axle.

All things being equal there is not that much difference except the independent being IMHO better on corrugations IF the solid axle is specified and maintained properly with regular checks of shackle welds, ubolts, centre bolts and main spring fatigue. Of course bearings should be checked and repacked or replaced before every long trip with both independent and solid.

Well my independent is now 17 years old and I should replace the springs as the paint is blasted off and I replaced the Koni shocks last year before yet another lap of OZ. The only potential failure points apparent on mine are the weld for the stub axle ( and this applies to solid) , the pivot bushes and they would only cause the alignment to be lost, and the coil spring, and if one broke the trailer would still be towable.
Regards Philip A

[Tank]

So Philip are you saying that I/S trailers do not lose ground clearance when loaded or travelling over rough or rutted ground, esp at the pivot point.
Because with a solid axle with leaf springs the lowest point is the c/l of the axle, you can also buy axles that don't have welded on stub axles as they can be machined onto the end of the axle bar. When a wheel on a solid axle travels up over, say a rock, then the tray of the trailer does the same, increasing ground clearance.
The lowest point on my C/T is the bottom of the axle which would be about 30mm below the c/l of the stub axle. (Springs sit on top of axle and U_bollts have nuts on top)
Most independent swinging arm setup w/coil spring and shock I have looked at have the bottom of the suspension arm level with where the rim and tyre meet and most were badly knocked about underneath.
To each his own, I suppose, Regards Frank.







All independent suspension camper trailers ( I have seen) have much MORE ground clearance than leaf sprung trailers. Also because they are camper trailers the suspension is usually pretty stiff so that people can walk around in them. The lowest point on mine by far is the spare wheel underneath, and it can only be where it is because it is independent.

The main benefit of independent , in my Camp'o'matic anyway is no skipping on corners at all, and no skipping on corrugations at all.
Mine is over engineered with parallel bearings with a load rating of 1500KG.
While there are more solid axle campers out there I have only ever seen failed solid axle campers never independent , maybe because there are many more failure points on a solid axle in spring centre bolts, u bolts, and shackle welds to frame. Shackle weld failure is the most common failure point according to the Coen RACQ recovery bloke, and he knows!

It is far easier to under specify a solid axle than an independent, as the parts are easily obtainable from any trailer parts supplier, so dodgy builders build to a price, while independent is usually part of a complete chassis and sold as part of an upmarket model.

I only once saw a photo in a 4WD magazine of a Camp'o'matic being limped home on a piece of timber on one side, and I thought how could that happen, and the answer must have been total neglect, as the parallel bearing must have seized so tight it ripped off the stub axle.

All things being equal there is not that much difference except the independent being IMHO better on corrugations IF the solid axle is specified and maintained properly with regular checks of shackle welds, ubolts, centre bolts and main spring fatigue. Of course bearings should be checked and repacked or replaced before every long trip with both independent and solid.

Well my independent is now 17 years old and I should replace the springs as the paint is blasted off and I replaced the Koni shocks last year before yet another lap of OZ. The only potential failure points apparent on mine are the weld for the stub axle ( and this applies to solid) , the pivot bushes and they would only cause the alignment to be lost, and the coil spring, and if one broke the trailer would still be towable.
Regards Philip A

[PhilipA]

Most independent swinging arm setup w/coil spring and shock I have looked at have the bottom of the suspension arm level with where the rim and tyre meet and most were badly knocked about underneath.

Mine has the axles welded on beneath the swing arm as I think all campomatics do, but that is a good point for the OP to note. So on a Camp'o'matic the lowest point is the axle same as a solid.

The only place I have really whacked mine is the back of the water tank, and slid the a frame. I have a spare underneath but because it is nested back near the axle it doesn't hit at all AFAIK.
Regards Philip A

[Vern]

I have no idea how the lowest point on the trailer is the trailer in an independent suspension model? Its definitely not on mine, its no different to a solid axle trailer.
Lowest point is the swing arm, even when fully loaded

[Tank]

Here's an Idea, if you have one of those R/C 4wd toy trucks with independent suspension all round, press down or move it over bumpy ground and watch the bottom of the chassis bottom out. On a solid axle the only way you would get the chassis under the trailer to touch the ground is to bend the axle and splay the wheels out sideways, Regards Frank.





I have no idea how the lowest point on the trailer is the trailer in an independent suspension model? Its definitely not on mine, its no different to a solid axle trailer.
Lowest point is the swing arm, even when fully loaded

[Vern]

Ahh there independent suspension is set up dufferent. Swing arms swing the opposite ways, 90degrees difference

[PhilipA]

On a solid axle the only way you would get the chassis under the trailer to touch the ground is to bend the axle and splay the wheels out sideways, Regards Frank.


Yes that is correct in theory, but the practice with off road trailers is that they are so far off the ground that you never touch the chassis and the suspension travel is not like an RC car, while on the other hand the axle of a solid axle trailer could drag on a high crown track.
Regards Philip A

[PhilipA]

Some photos of my old Camp'o'matic suspension.

90079

90080

90081

Regards Philip A

[Hoges]

Very solid set up!:D What puzzles me however is that the (45 deg? or is that parallax error?) angle of the shock absorber mounting means that they do not get to operate very far on their stroke unless there is significant displacement of the axle arm ... which means that their damping effectiveness is somewhat reduced compared to a more vertical arrangement:eek:

[Tank]

Philip, I know mate, I was using a simplified version to explain to Vern who posted he didn't (and still doesn't) understand the principle.
I like solid axle trailer suspension because the principle works better off-road.
Wheel travels up, so does the trailer body, the ground clearance stays the same loaded or unloaded, the distance to the ground under the centre of the axle stays constant unless you bend the axle. The underbody of the trailer directly above the axle can not change it's distance to the ground once the springs are bound or flat and the trailer is sitting on the axle (Ground Clearance)
An I/S trailer can be loaded to the point where the underbody of the trailer will actually sit on the ground under the inner pivot points or the wheel guards will sit on top of the tyres or the springs bind.
Simple fact if a trailer has I/S when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.
For every ACTION there is an equal and opposite Reaction, Regards Frank.









Yes that is correct in theory, but the practice with off road trailers is that they are so far off the ground that you never touch the chassis and the suspension travel is not like an RC car, while on the other hand the axle of a solid axle trailer could drag on a high crown track.
Regards Philip A

[PhilipA]

Very solid set up!:D What puzzles me however is that the (45 deg? or is that parallax error?) angle of the shock absorber mounting means that they do not get to operate very far on their stroke unless there is significant displacement of the axle arm ... which means that their damping effectiveness is somewhat reduced compared to a more vertical arrangement:eek:

Yes AFAIK 1997 was the first time they offered Independent and they were probably still learning. But they work well. I don't recall the trailer has ever skipped on a corrugation.

Later ones have the shocks angled backwards, but they all have some type of angle to them so that the bottom of the suspension is not too far from the floor I guess.
The shocks are F100 I beam front shocks so they are heavily valved anyway. They work very well as I found out when I replaced my old ones which had a damaged foot valve from bottoming even though there are large progressive bumpstops ( after 17 years!). Maybe from when I made about 10-15 metres air once on the way to Kulumburu.

Regards Philip A

[Hoges]

I had something similar happen on the PRD towing our home made camper trailer south towards Coen... Despite being briefed by eldest daughter who in those days travelled the route regularly and SIL had even prepared a set of detailed 'track notes' for us, I was paying particular attention and sitting on a steady 75-80km/hr ('tradies' were passing at over 100km/hr...) ...the 'rise and dip' was camouflaged in the afternoon sun...it's not an experience I would willingly repeat...

[Vern]

Philip, I know mate, I was using a simplified version to explain to Vern who posted he didn't (and still doesn't) understand the principle.
I like solid axle trailer suspension because the principle works better off-road.
Wheel travels up, so does the trailer body, the ground clearance stays the same loaded or unloaded, the distance to the ground under the centre of the axle stays constant unless you bend the axle. The underbody of the trailer directly above the axle can not change it's distance to the ground once the springs are bound or flat and the trailer is sitting on the axle (Ground Clearance)
An I/S trailer can be loaded to the point where the underbody of the trailer will actually sit on the ground under the inner pivot points or the wheel guards will sit on top of the tyres or the springs bind.
Simple fact if a trailer has I/S when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.
For every ACTION there is an equal and opposite Reaction, Regards Frank.

I know exactly how it works frank, I have an independent suspension camper trailer, as well as leaf sprung old camper. The ones you speak of must have very long swing arms to do what you say?

[C00P]

Towed our camper trailer (about 1 tonne) across Nullarbor, up the west coast, out to Kennedy Range, and Karajini National park (some solid corrugations there), up Gibb River Road, down to the Bungles and in to the camp site (probably one of the roughest sections), and a few other places with plenty of rocks and river crossings. Simple leaf suspension, no shock absorbers. Always stayed behind the car (up to 130kph for a short burst in the NT just to see what that felt like) and no problems for the entire 15,000km. Lost a bit of paint from stone impact, that's all. Set it up with 60kg on the tow hitch (Treg Hitch) and weighed it before we left. Had electric brakes.
I think there is a lot of hype about trailer suspensions- unless you are towing some very impressive weights, or you have the trailer loaded incorrectly and it starts swaying. Keep it simple, I reckon.

Coop

[SouthOz]

Philip, I know mate, I was using a simplified version to explain to Vern who posted he didn't (and still doesn't) understand the principle.
I like solid axle trailer suspension because the principle works better off-road.
Wheel travels up, so does the trailer body, the ground clearance stays the same loaded or unloaded, the distance to the ground under the centre of the axle stays constant unless you bend the axle. The underbody of the trailer directly above the axle can not change it's distance to the ground once the springs are bound or flat and the trailer is sitting on the axle (Ground Clearance)
An I/S trailer can be loaded to the point where the underbody of the trailer will actually sit on the ground under the inner pivot points or the wheel guards will sit on top of the tyres or the springs bind.
Simple fact if a trailer has I/S when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.
For every ACTION there is an equal and opposite Reaction, Regards Frank.

I thought that the idea of suspension was that the trailer didnt move and that the wheel did?

Your saying that once the spring are bound or flat like its a good thing?
If you had 200mm of ground clearance and 100mm of suspension travel, once your springs have bound or flattened, you now have 100mm of ground clearance?

Simple fact if a trailer has I/S when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.

Simple fact is that the swing arm pivots on the opposite end to the wheel. The force is applied to the spring. If it pivoted at the spring mount then the opposite end would travel down.

Dave

[Tank]

Some new laws of physics, you should publish, Regards Frank.







I thought that the idea of suspension was that the trailer didnt move and that the wheel did?

Your saying that once the spring are bound or flat like its a good thing?
If you had 200mm of ground clearance and 100mm of suspension travel, once your springs have bound or flattened, you now have 100mm of ground clearance?

Simple fact if a trailer has I/S when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.

Simple fact is that the swing arm pivots on the opposite end to the wheel. The force is applied to the spring. If it pivoted at the spring mount then the opposite end would travel down.

Dave

[PhilipA]

Wheel travels up, so does the trailer body, the ground clearance stays the same loaded or unloaded

Substitute "axle" for "body " and it makes sense.

This idea of body ground clearance applies to independent front suspension 4x4s where the diff housing /stone guard are the lowest point on the cars Vs a solid axle where the diff moves up and down with the wheel.

LR3and 4 by contrast have the diff tucked up in the chassis rails thanks to Fords Chassis hydroforming techniques and so it is not the lowest point.

So the answer re ground clearance is "it depends" on the design of the independent vs solid.
Same with trailers. AFAIK , no camper trailer has components hanging down to snag if the suspension is compressed.
Regards Philip A

[Chucaro]

Suspension Comparison

[gusthedog]

Suspension Comparison (https://www.youtube.com/watch?v=ADoLPq2L0qE)

Exactly what happens in my experience. I have owned all types and nothing even compares to independent suspension. We just picked up our third camper trailer on the weekend. Its a 2011 Xtrail, with independent suspension and its just fantastic off road.

So you keep your leaf suspension or alko torsion bar etc and I'll stick with my crappy, unreliable, coil sprung, comfortable D2 and camper that matches :D

[roverrescue]

I think we have thrown this issue around the campfire a few times previously but maybe it is time for me to chime in once more...

First that cruisemaster video simply demonstrates that poorly chosen leaf suspension rides badly.
What many miss is the terrible uncontrolled left right load shifting in the inde setup.

My two critiques of inde setups are - as above uncontrolled left right control
If you sat in you super special inde trailer you would likely get sea sick pretty quickly
A single axle trailer is a tripod - it needs none or nearly none left right articulation.

My seond critique is unecessary tyre wear / or alignment requirements.


" But why doesn't someone make a solid axle with coil springs"

As Erich intimated this above question is the question and I think you will find a few example of custom made trailers with soft riding either coils or airbag solid axles. This fixes the left right load share and also reduces tyre wear to near zero.

This year I will build another two fixed axle coil sprung boat trailers. Honestly I see absolutely no advantage to inde sprung other than it is commercially available. My triangulated 4link uses twice as many joints as independent swing arms but the benefits outweigh the negatives.

Inde setups are popular solely because they can be made in a jig and then welded into any width chassis. A solid axle linked suspension becomes custom fit and finish. Perhaps overkill for a trailer but pizzles all over an inde setup ;)

Steve

[roverrescue]

Just to bring a few things together

some links of stuff I have glued together and some opinionated ramblings:

http://www.aulro.com/afvb/trailers-vans-campers/178035-chassis-build-box-trailer.html

http://www.aulro.com/afvb/trailers-vans-campers/174206-cross-forum-link-interesting-read.html

http://www.aulro.com/afvb/trailers-vans-campers/131001-offroad-boat-trailer.html


ps I have used leaf springs on a few boat trailers - my favourite are 78/79 series leaves super long super supple and nearly unbreakable. Requires a pretty unique chassis to carry leaves that are nearly 1.5m long though!!!!!!


Steve

[SouthOz]

Well frank we will have to agree to disagree.

The solid axle really performs well in the 3 trailer comparison.

Dave

[roverrescue]

That VC video is a little like the Etec vs Yamaha advertisment from a few years ago ;)

Anyways, two observations.

I dont love how they have set up the dampers but I understand they want a neat and compact set up but there has to be a more efficient method. Those dampers are running <30% efficiency

I do like how they have set up their shackle on the inde leaf. I see so many trailers with the shackle nearly verticle. This in itself greatly increases spring rate as all spring is dependent on the spring. If the shackle sits at ~45 degrees when loaded, this will reduce spring rate and improve ride. As mentioned above, run some 78 cruiser leaves with shackles on the right angle and the spring rate will be as soft as coils.

Steve

[SouthOz]

OK I would like some one to explain to me how this can be loaded to the point that the pivots can touch the ground and when a wheel/s travel up, the opposite end of the swivel/trailing arm travels down.

Dave

https://www.aulro.com/afvb/images/imported/2015/02/577.jpg

[Vern]

That's what I was trying to say dave. But according to frank I have no idea.

[modman]

Track got it right in the nineties with 60 series leaf springs
google track eagle, mirage or oasis
Later models got the sugar glider independent for a short time, then mc2 style was introduced
Arguably the best constructed trailers STILL going around today

Short trailer springs belong on golf buggies;)
I've always wanted to build a trailing arm independent trailer suspension like the track mc style with d2 rear gear( with watts link;)

Steve, what's the difficulty using cruiser ute leafs (sprung under) on a trailer?
Wouldn't the hanger and shackle bush sit on/in the outside/frame rail?
Do you envisage any problems?


David

[roverrescue]

David

78/79 springs are around 1400mm long eye to eye
So you will need about 1500mm of chassis to attach front and rear hangers

This means the springs are wayyyyy longer than your guards

Not difficult but packaging could be difficult. I have installed them on two boat trailers.
With a pair of dampers and running the leaf packs sans load leaves and removing one or two thin leaves they ride as smooth as coil spring trailers I have built.

As they are on boat trailers I made up some 50mm b 50mm by 5mm angle slides that each shackle welded to. These slides were then bolted to the underside of the chassis rails.
Works well on boat trailers and lets you adjust to ball weight.

Bit harder on a camper trailer where you likely dont have clean chassis rails to attach to.

Independent swing arms are popular because they are neat to package NOT because they are a superior suspension design. I agree that the Track cross linked swing arms is a very well designed suspension.

On independents, lack of left right load sharing means you need to run higher spring rates and thereby have less control. Now that may not be an often experienced problem but it certainly is not a superior suspension design.

Just running ARB would likely improve the performance of inde trailers but I guess that removes some of the neat packaging

S

[roverrescue]

Would love to know the story on this;

http://www.exploroz.com/uploads/members/3863.5/4__TN135x100.jpg?_112771

But not surprised at the location of failure. The inner arms of inde swing arms have to take huge loads due to leverage and poor geometry

I know this kind of failure is not particularly common but interesting none the less

s

[David Hannett]

I had a camper trailer with torsion bar suspension for about 4 years 1000kg loaded over a lot of rough 4x4 terrain and although it performed well for ride and stability its simply wasn't strong enough and the bars would progressively sag (metal ends adjacent to the wheels would bend gradually under the load) so not recommended - nothing ever broke though - cheers