Camper Suspension

Michael1001 · Newbie

Camper Suspension

Peter_n_Margaret · Guru

For performance, cost and reliability fit some longer than normal leaf springs with an appropriate spring rate.
There is absolutely no value in independent suspension on a trailer.
Cheers,
Peter

oldbloke · Guru

Peter_n_Margaret wrote:
For performance, cost and reliability fit some longer than normal leaf springs with an appropriate spring rate.
There is absolutely no value in independent suspension on a trailer.
Cheers,
Peter

Agree. Ive never understood fitting independent suspension to a van.

Izabarack · Guru

Michael1001 wrote:
An option is the Australian made COUPLEMATE suspension.

I went past them for the suspension on my van after looking at the engineering specs. I put Cruisemaster with Air Bags and double shocks on my off road van. I did Birdsville and all the Central west a few times and more corrugations than should be endured, all without issue. Independent suspension pays for itself if travelling on sandy tracks often used by the Landcruiser and Patrol crowd. Air bags are fantastic for overnight levelling, getting the van or trailer close to the ground (smaller step up for the missus), and reducing corrugation vibration effects on electronic equipment. Im not a drinker but have seen many a beer can rubbed through after an hour on an outback track.

Few years ago, friend from Aviation Maintenance put some accelerometers on my van and that of a travelling companions. Air bags won, big time.

PeterD · Guru

Iza, Were you comparing your air suspension with air suspension on beam axles. Or were you you comparing your suspension with spring type independent suspension? The op was intending to fit spring type suspension, not air type suspension.

I suggest it was not a case of independent suspension winning over beam axle suspension but air Vs spring suspension. Your reply has little to do with the OP's situation.

read - Is Caravan Independent Suspension Necessary

-- Edited by PeterD on Thursday 24th of February 2022 08:01:09 PM

Aus-Kiwi · Guru

Trailing arm is independent suspension. Is it hitting bump stops . Or is weight in excess of chassis ? Maybe stronger welded in
Frame

Hitting the road · Senior Member

Independent suspension every time...firstly all the wheels & tyres remain vertical through out their travel and therefore, secondly does not have any affect on the opposite wheel / tyre if dropped in to a rut, which gives a much smoother more controlled ride.

If you have ever followed a van or trailer with a solid axle on a rutted road, the solid axle trailer will pitch and roll as when ever one wheel drops in to a rut the opposite wheel leans in or out to compensate as it is solidly connected, where as the independently sprung unit will travel more level with far less pitch and sway.

The only thing I see as an overkill in many applications is two shock absorbers per wheel...not necessary at all imo if decent shocks are fitted in the first place. I had a camper trailer with independent suspension, only weighed 1350kg loaded and had twin shock absorbers each side...why?

My current van has dual axles with independent suspension, one shock absorber per wheel, tows extremely well, dead straight with no sway, bounce or pitch.

Bobdown · Guru

Hitting the road wrote:
Independent suspension every time...firstly all the wheels & tyres remain vertical through out their travel and therefore, secondly does not have any affect on the opposite wheel / tyre if dropped in to a rut, which gives a much smoother more controlled ride.
If you have ever followed a van or trailer with a solid axle on a rutted road, the solid axle trailer will pitch and roll as when ever one wheel drops in to a rut the opposite wheel leans in or out to compensate as it is solidly connected, where as the independently sprung unit will travel more level with far less pitch and sway.
The only thing I see as an overkill in many applications is two shock absorbers per wheel...not necessary at all imo if decent shocks are fitted in the first place. I had a camper trailer with independent suspension, only weighed 1350kg loaded and had twin shock absorbers each side...why?
My current van has dual axles with independent suspension, one shock absorber per wheel, tows extremely well, dead straight with no sway, bounce or pitch.

X 2

Peter_n_Margaret · Guru

Hitting the road wrote:
The only thing I see as an overkill in many applications is two shock absorbers per wheel...not necessary at all imo if decent shocks are fitted in the first place. I had a camper trailer with independent suspension, only weighed 1350kg loaded and had twin shock absorbers each side...why?
My current van has dual axles with independent suspension, one shock absorber per wheel, tows extremely well, dead straight with no sway, bounce or pitch.

One of the very big advantages of leaf springs is the self damping effect provided by the friction between the leaves. Coil springs do not have that advantage which means the dampers have MUCH more work to do, so they don't work as well and they will wear out quicker. Therefore twins are typically fitted.

Dual axles with independent suspension do not load share. It is therefore likely that in undulating conditions that individual wheels and tyres may be easily overloaded. It is a legal requirement for some dual axle trailers to have load sharing suspensions for that precise reason.

Cheers,

Peter

Michael1001 · Newbie

Thanks everybody for your input, and thanks Iza for answering my question.
Was there something in particular about the engineering specs that concerned you?

Michael

Izabarack · Guru

Michael1001 wrote:

Was there something in particular about the engineering specs that concerned you?

No specific concern, just decided Cruisemaster with air bags would be better for my intended use of the van, although I do remember being impressed on the specs for the bearings on the Cruisemaster. I definitely wanted Air Bags as I was intending on doing lots of outback dirt. For my application, independent was a no brainer. I was working in Aerospace engineering at the time and knew a bit about isolating stuff from vibration effects.

if you are updating around cracking problems, I suggest twin shocks and the specs of the shocks are important.

KJB · Guru

Izabarack wrote:
Michael1001 wrote:

Was there something in particular about the engineering specs that concerned you?
No specific concern, just decided Cruisemaster with air bags would be better for my intended use of the van, although I do remember being impressed on the specs for the bearings on the Cruisemaster. I definitely wanted Air Bags as I was intending on doing lots of outback dirt. For my application, independent was a no brainer. I was working in Aerospace engineering at the time and knew a bit about isolating stuff from vibration effects.
if you are updating around cracking problems, I suggest twin shocks and the specs of the shocks are important.

Multiple large shock absorbers give greater control as they work easier and have a greater capacity to dissipate the generated heat and so continue to operate effectively. (extreme examples of this can be seen on "OffRoad Racing Buggies - the shock absorbers are not there just for their looks... ) Australia's long stretches of corrugated and or undulating roads make shock absorber use important no matter if you are using leaf spring, coil spring , rubber or air bag suspensions. KB

oldbloke · Guru

KJB wrote:
Izabarack wrote:
Michael1001 wrote:

Was there something in particular about the engineering specs that concerned you?
No specific concern, just decided Cruisemaster with air bags would be better for my intended use of the van, although I do remember being impressed on the specs for the bearings on the Cruisemaster. I definitely wanted Air Bags as I was intending on doing lots of outback dirt. For my application, independent was a no brainer. I was working in Aerospace engineering at the time and knew a bit about isolating stuff from vibration effects.
if you are updating around cracking problems, I suggest twin shocks and the specs of the shocks are important.
Multiple large shock absorbers give greater control as they work easier and have a greater capacity to dissipate the generated heat and so continue to operate effectively. (extreme examples of this can be seen on "OffRoad Racing Buggies - the shock absorbers are not there just for their looks... ) Australia's long stretches of corrugated and or undulating roads make shock absorber use important no matter if you are using leaf spring, coil spring , rubber or air bag suspensions. KB

That's fair. But it assumes most do lots of kms on dirt roads. So it's horses for courses.

Izabarack · Guru

KJB wrote:
long stretches of corrugated and or undulating roads make shock absorber use important

Yes. Interesting experiment is to check the temperature of your shocks after travelling Dalby to Chin-Chill-Are.

Vibration isolation, especially against cracking in affected components, rarely incorporates shock absorbers as discussed here. Rather spring compression and lengthening rates are matched to the mass to be supported. Air Bags are particularly good as inflation pressure can be easily adjusted if the load being carried by the vehicle varies.

Vibration isolation techniques at the brutal end of examples are seen in engine and transmission mounts. Alternatively, I have seen an inflated party ballon version of bubble wrap used to pack delicate items for transport.

Ivan 01 · Guru

I cant help you with a report on the Couplemate Suspension but if it is Aussie made then that would most likely be a good start.

Leaf or semi elliptic springs on campers and caravans are last century technology.

The comments of the observations from some as to how unsuitable this suspension is for caravans is testament to the reasons that most modern manufacturers use independent suspensions today, as opposed to the ancient technology.

Peter_n_Margaret · Guru

What trailer suspension does the military use?
They want performance and reliability and are not subject to the whims of fashion.
Cheers,
Peter

Ivan 01 · Guru

Peter_n_Margaret wrote:
What trailer suspension does the military use?
They want performance and reliability and are not subject to the whims of fashion.
Cheers,
Peter

I have been wondering over recent times do the Australian Army get their box trailers made in China. hmm

Izabarack · Guru

Peter_n_Margaret wrote:
What trailer suspension does the military use?
They want performance and reliability and are not subject to the whims of fashion.

Close enough is good enough for most military applications. Trailers are essentially throw away items. Tenders for supply will/would specify load carrying capacity and tyre size. Tender evaluation is always biased toward cost. Acceptance testing of supplied equipment will document a testing procedure. Performance and reliability requirements are just too expensive to specify.

Aus-Kiwi · Guru

A good set up no matter what type ! The main issues with beam axle is centre clearance when or if traveling on tracks . Most didnt have shock absorbers., Fitting shocks to leaf springs pretty much brings them up to better system. The main part here is durability. If the sub frame has cracked ? Its not quite the suspension type ! Its more the poor steel, design used !! Twin shocks would spread the load . They are usually mounted EACH side of the trailing arm. Makes it better on bushes ! Keeps alignment.

Clarky 1 · Senior Member

Those Army box trailers are a disposable item. They would have thousands of them.
I believe the tare on the 6 x 4 box trailer built for the army is 400+ kg with the standard tarp type cover.
This is why they are so unbreakable.
There design is such that speeding is not even thought of. 80 klms per hour would be generous.

Most box trailers built today for use by tradies and home gardeners are built with semi elliptic springs probably only due to cost and simplicity. They certainly dont follow the build plans of an Army unit and neither does any camper or caravan built for private use.

Most of the camper trailers and caravans this century are built with or have the option of independent suspension options.

-- Edited by Clarky 1 on Thursday 3rd of March 2022 02:48:51 PM

Craig1 · Guru

not quite a boxy ,but

davidcamper · Newbie

Hi. We have a similar issue with our Goldstream wing 2 2005. How did you do getting replacement springs? Thx

jegog · Senior Member

Five years ago I had cause to visit the engineering mob that does, among other things, van repairs in Weipa. He told me that they have a van or camper come in at over one a month for suspension repairs. Always the leaf spring suspension and often it is the connecting axle broken where the two halves are welded together.

Cuppa · Guru

I consider that the MC2 assymetrcl suspension on my Tvan is as good as it gets, better than any other off road towed trailers & van suspension worldwide. Longer travel & better ride than with conventional swinging arms or leaf springs & soaks up the corrugations without hint of bounce. Never had any corrugation induced damage inside & we have been over a lot. Initially designed for the military to carry 'sensitive' radar equipment.

https://www.tracktrailer.com.au/company-history/mc2-suspension/

Michael1001 · Newbie

Hi DavidCamper,

My suspension was an early design trailing arm and I replaced it with a Simplicity Axles design independent suspension, manufactured in Melbourne.

Simplicity could not recommend a repairer in NSW and referred me to their distributor in Warwick, Queensland, Absolute Trailer Solutions. I accepted their proposal and travelled 1000km from my home to Warwick. They made a complete hash of the job. The workmanship was careless and their attitude was bad. I took it back to them and they fixed most things but the suspension was riding on the bumpstops and nobody could tell me why. I took it back a third time and it was discovered that the hangers were installed too close together by 67mm and the whole lot had to be removed and re-installed.

Would I refer anyone to Simplicity Axles or Absolute Trailer Solutions? Definitely not!

DavidCamper, I know that this doesn't answer your question, but it feels good to get it off my chest. And perhaps tells you where not to go.

davidcamper · Newbie

Thanks for the response. Goldstream are not helpful at all. I got the camper home ( 3 month wait for a check up ) and found one of the trailing arm bracket had come away from the chassis. Trying to get a welder to fix it but then back to the spring issue. Not broken at least but 20 years old so I would like to replace.

PeterD · Guru

Michael1001 wrote:
Would I refer anyone to Simplicity Axles or Absolute Trailer Solutions? Definitely not!

Problems with a new installation would not be a problem caused by the manufacturer. It would be installation problems. You are slanging off at the wrong mob. I suggest Simplicity deserve an apology from you.

Did you go back to Simplicity and report the treatment that was metered out to you? You should be protecting future customers from the same treatment that you got.

davidcamper · Newbie

Can you give me a ballpark figure for the suspension upgrade? Did you have a camper trailer or a caravan. Thx

BAZZA44 · Senior Member

Simplicity Suspensions were originally developed for the army. There is nothing wrong with them. They are one of the very few load sharing, independent suspensions. Michael your issues are with the repairer.

Yes my van has Simplicity, rides well anywhere.

Barry

jegog · Senior Member

Izabarack wrote:
Peter_n_Margaret wrote:
What trailer suspension does the military use?
They want performance and reliability and are not subject to the whims of fashion.
Close enough is good enough for most military applications. Trailers are essentially throw away items. Tenders for supply will/would specify load carrying capacity and tyre size. Tender evaluation is always biased toward cost. Acceptance testing of supplied equipment will document a testing procedure. Performance and reliability requirements are just too expensive to specify.

What a lot of claptrap! Supplying the military is all about compliance certification as anybody who has worked in supplying military equipment knows.

Now maybe box trailers are designated as disposable and not subject to their acheduled maintenance protocols, but your statement said "Close enough is good enough for most military applications" which is profoundly untrue.