suspension

Submitted: Saturday, Aug 18, 2012 at 07:24
ThreadID: 97491 Views:6163 Replies:3 FollowUps:5
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Been a sleeping member for a while and this is my first post. We are looking at buying a second hand van around the $50,000 mark and would like to do a few dirt roads free camping trips. Nothing too serious. Looking at the Crusader Inspiration with beam axles and rocker roller suspension. Hope that would handle light corrugation with slow speed OK. Like the independent but not too many around. Any opinions on the above would be appreciated.
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Reply By: member - mazcan - Saturday, Aug 18, 2012 at 12:32

Saturday, Aug 18, 2012 at 12:32
hi ronc2
i just googled the top
i asked ----
whats the best suspension for a caravan on dirt/off rd
and it came up with 32900 results
google is your friend and any topic that is dicussed on explore oz usually will come up on google
its just a mater of how you put the question to google
if you use various questions related to the top you will get a variation of different answers enjoy the hours of reading ps im not trying to fob you off e oz
just a helpfull sugestion some poeple dont realize the above
cheers barry
AnswerID: 493116

Reply By: Member - nick b - Saturday, Aug 18, 2012 at 19:00

Saturday, Aug 18, 2012 at 19:00
Gooday Ron : bean axle , rocker suspension would have to be the most popular type of suspension set up for carrying big heavy loads i would think . as you say independent my be better but a lot more moving part , more things to brake down on you !!

just as important is how the suspension is welded to the chassis ( engineered )
and driving to the road conditions .

The beam axle type of suspension will work fine in all type of terrain you are talking about here .

good luck with your purchase ......
Cheers Nick b
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AnswerID: 493131

Follow Up By: Member - Andrew W14 - Saturday, Aug 18, 2012 at 21:41

Saturday, Aug 18, 2012 at 21:41
Just because a system is 'the most popular' type means nothing. The main reason its the most popular is that very few manufactureres offer anything else - simply because its the cheapest most readily available system.

Do your research properly - look at, for example VC air or coil suspension, Sugar Glider systems, and many more. All offer a substantial benefit to the crude, shake your van to pieces, beam axle type. And most are not 'welded to your chasis', but an integral part of it.

True - rocker. roller will 'work' in all types of terrain - but will it work the best?

My experience an 3 systems shows its far from the best - but yes its the cheapest and most fitted for reasons above!
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Follow Up By: Member - nick b - Saturday, Aug 18, 2012 at 22:12

Saturday, Aug 18, 2012 at 22:12
when all else fails return to plan ..(A) ... KISS ....

Cheers Nick b
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Reply By: Member - Wamuranman - Sunday, Aug 19, 2012 at 10:04

Sunday, Aug 19, 2012 at 10:04
Hi Ron,


Here is some information which I hope you will find helpful in your deliberations. I do not wish to get into an argument about suspension but Andrew is correct – just because something is commonly used does not mean it’s the most suitable.

The Laws of Physics (Hooke’s Law) identify that are some significant scientific benefits of independent suspension. There are 2 proven general benefits of independent suspension (IS).

(1) IS leaves a tunnel underneath the centre of the van for better clearance – an axle suspension can drag the axle when the wheels fall into a rut and will act like a boat anchor to bog the tow vehicle.

(2) But the most compelling reason to have IS is an engineering one- IS breaks up “harmonic motion”. Harmonic motion means that at a particular speed of travel on ruts or corrugations the “bounce” will build on itself to create a destructive force. This force can (in some cases) be sufficient to catastrophically fail a beam axle/leaf suspension system.

Hooke’s Law states that the amount a spring will be compressed or stretched from equilibrium is directly proportional to the applied force. This is why most IS systems also employ shock absorbers – a device that removes energy stored when the spring is compressed (eg by pothole in road). Normally a shock absorber works by pushing a fluid through a small hole by a piston. As the fluid is pushed through the small hole it is heated thus converting the stored energy to heat which is dissipated into the atmosphere. This allows the spring to return to equilibrium without “overshooting” the equilibrium point.

I researched suspension systems about 12 months ago before ordering a new van (incl a discussion with a friend who has a PhD in mechanical engineering). I am convinced IS is significantly better than beam axle suspension and chose for our new van independent trailing arm coil suspension with 8 shock absorbers. Our brand is Cruisemaster but there are others –G&S, Simplicity, Sugarglider etc. If you do a search on these words in the secord hand caravan web sites you should find some for sale (also try the word independent in searching of course).

Of course whatever van and suspension you get you must always drive to the prevailing conditions. But I noticed on a recent (first) trip on a corrugated road our van sat beautifully level on the corrugations without bouncing all over the place like some we were following.

Good luck in whatever you choose and happy caravanning.
Cheers

AnswerID: 493168

Follow Up By: awill4x4 - Sunday, Aug 19, 2012 at 16:39

Sunday, Aug 19, 2012 at 16:39
I am with you entirely Wamuranman.
In my instance, I can't afford a new or even 2nd hand "offroad" van with independant suspension so I went about converting the "onroad" van I already own.
My wife an I are basically happy with it and we own it outright so I went down the line of stiffening the chassis myself (I'm a full time welder so that side of things didn't worry me at all.)
I researched a bit about the Vehicle Components system, the Control Rider system from G&S Chassis and in the end decided on retro fitting a SugarGlider system from Withers Engineering as it seemed to tick all the boxes for me.
I had the guys at Withers Engineering fit the suspension and associated crossbars and bracing as they have the experience and overall the fitting of the suspension was only a small part of the actual cost.
You will notice on the pics below it's set up for twin shock absorbers per wheel. I was at my limit money wise so Neville optioned it up so I could fit the shocks at a later stage if I feel I needed it.
I've only had it back a week and I've still got lots of work to do on the van fitting drop down legs, water tanks etc, so I haven't had a chance to put it through its paces but I'm confident it will suit my needs well.
The pics below give an idea of how the SugarGlider system is installed.
Regards Andrew.









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Follow Up By: Member - Wamuranman - Sunday, Aug 19, 2012 at 16:54

Sunday, Aug 19, 2012 at 16:54
Hi Andrew,

That looks a really robust job. Well done.
Your springs look larger than mine..what size are they (diametre)?
Very solid looking job.
Here is a photo of mine...can't see the springs very well but look smaller than yours?
Cheers

Image Could Not Be Found


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Follow Up By: awill4x4 - Sunday, Aug 19, 2012 at 18:03

Sunday, Aug 19, 2012 at 18:03
The springs are 22mm diameter but you have to take into account that the weight of my van (currently 1530 kgs as it sits with an estimated ATM of between 1900 and 2000 kgs) is supported by one axle set not 2 like yours, so the spring rate must be higher.
Removing the square 50mm axle/leaf spring assembly and changing to the SugarGlider has increased the weight by around 110-120 Kgs (We weighed it before and after). I'm not too unhappy with that as there is some serious steel work in both the arms and the associated crossmembers they are mounted to.
I'll probably go down the route of twin shocks per wheel like your VC system as finances allow.
My priorities are drop down legs, water tanks and some extra stiffening of the outriders that support the body walls of the van.
Once those are done, I can at least use the van and then it's down the battery/solar power path so I can experience the free camping lifestyle.
Regards Andrew.
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