Member - Lotzi (QLD) replied:

Hi Roachie

Gee, I hope fellow forum members really read what you have written and digested what is said . . .

I am a firm believer in air bag suspension, as we were endeavouring to have Denning air bag 4x4 and 6x6 coaches built for tour work on Fraser Island in 1989, for your Roachmobile, it is possible, but in today's climate must be engineered, but done properly, you wont regret it.
I have used air bag suspension on just about all hi ways, including some that have only recently been sealed, just great.

The big thing that I got out of your thread is the fact of weight, insurance issues and liability, any time I have mentioned that some vehicles are over weight on this and other forums I have usually had a very clever verbal comment, of which I don't have the verbal ability are desire to respond to.

In the end, if forumites are going to let the world know how clever they are as far as weight issues go, just remember that there is a big world out there reading what you are publishing.

if you can get a decent air bag set up, go for it.

Cheers all

Lotzi

Robin Miller replied:

I cannot comment specifically on SA law Roachie , but I think you will find some short cuts in what you were told.

I have only bothered to have mine verified , but it essentially is this about the tyres.

For placard , in Victoria the law actually stated as largest tyre approved on that model car by manufacturer of which a local placard is but a derivative but not the same thing.

Hence My 2002 Patrol manual lists 245/85/16 tyres as an option in UAE I think.
which are significantly taller than 265/75/16 and then in vic you could go up on this 15mm making some but not all 33 inch tyres ok.


Air bag suspension wobbles - don't do it.

As for weight , I agree you should never overload these cars and mine is lighter than standard despite having winch lockers etc , this is why I steer away from things like bullbars and big dual batteries as a real cost benefit analysis does not show them in a good light.

Dave B ( BHQ NSW) replied:

Bill, in regard to the internal mirror, hasn't the cheese got a lovely little mirror behind her sunvisor?

That's a fixed one in my opinion.

Dave

viz replied:

Having had all sorts of suspension mods on various 4WD, and now airsprings on the Bruiser (rear only) I can say with great confidence, it is the best move I have ever made in suspension mods...

Just done 5000 km to the Red Centre and back (from Sydney) with the airsprings and a heavy load - drove like a Range Rover... Well the rear did anyway. The front is variable rate coil, 2" lift from Lovells - I am still thinking about that one - did not cope as well. I use Tough Dog adjustables - go well with the airsprings, not so good maybe with the coils. Tighten up for low and heavy, loosen off for high and light loads.

Upside - variable ride height - and when travelling on the tar, low is good; in the boonies - high takes all the pain out of the washouts, yumps and roller coasters. And I reckon it travels better on the horrugations.

Downside - bloody dear to buy; and you need a good compressor. I broke a bolt on the compressor mounts (I use an Endless Air 8 cfpm pump driven by the engine) and had to use a little Bushranger back-up pump - took about 10 minutes to pump up the bags to 80 psi. You also have to think long and hard about how you hook up the airbags to the air system and operate from inside the cockpit - the off-the-shelf item is a bank-breaker. Made my own.

Maintenance? Real real easy. I carry a spare for the bush, takes 20 minutes to change over - the missus could do it while you give advice and chug a beer...

The Patrol goes real well on Airsprings, due to its "primitive" suspension design. Cruiser 105 front needs some mods; Cruiser 100 IFS cannot do. Pity.

(Wonder if the 200 front could have them??)

viz

Member - John replied:

Roachie, have seen the results on a GQ, worked, but to my mind it works in reverse to the way it should, when you want lots of flex and compliance in the suspension, ie, max ground clearance, the air bags are pumped to the max, limiting the suspension travel and when you lower the bags, lots of suspension flex which is what you don't want.............Hope that makes sense?

Ozhumvee replied:

Roachie, don't go the airbag route, they work fine on the bitumen and good dirt but can't hack the work off road.
On our trip to the Geo centre of the Simpson last year we had a 79 turbo tray with airbags in the front and polyair type assist in the rear with the standard leaves. After a few days of very rough cross country going the RHS front bag had punctured due to insufficient clearance between the chassis and the airbag, we stuffed it full of sand but eventually cut up a floor mat to add to the bump stop to enable the vehicle to crawl the remainder of the distance to Birdsville.
There are a few problems with airbags, you can't maintain ride height and have suspension flex/compliance it is one or the other. You get drop but none or limited compression. When you let them down to restore some give in the suspension they then allow too much sideways movement and rub.
The mounts used to mount the bag to the diff are very light and not suited to extended off road use. The vehicle above eventually tore them off the diff housing. He did carry a spare airbag bellows but as the bottom mount had smashed (it is only alloy held to the diff housing with TWO little bolts) we were unable to repair it. He has since refitted the standard coil setup with aftermarket coils.
We also met a Nissan traytop on the CSR this year who was having problems in the rough corrugated conditions with the vehicle slowly breaking up. He found dropping the airbags to a pressure point to soften the ride meant it was virtually on the bumps stops which were then hammering the vehicle due to the lack of suspension travel. Pumping them up meant that it rode too hard again transmitting the road shocks to the vehicle and occupants. He freely admitted that he should have just gone the heavier spring route.
I've no doubt that there are thousands of heavy vehicles clocking up millions of k's on all sorts of roads but they all have limited suspension travel.
Unfortunately unless the vehicle is designed by the manufacturer to have the airbags as standard I'd leave it alone, the airbag sellers seem to want a shi!load of money for poorly designed and executed fitments.

Willem replied:

I was going to say something but have decided against it....hahahaha


Cheers

Squizzy replied:

Hey Bill,

If you know Ken in our club, he has full air bag suspension in his GU fully controlled from the cab.

I will send you his contact number via email.

Geoff.

Nomadic Navara replied:

Here is an interesting bit I OCRed from Australian Caravan +RV Oct/Nov page 61:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ESC VEHICLES AND THE LAW

ESC is mandated on all passenger-carrying vehicles sold in Australia from 2011. Because the programming relies on parameters such as engine and transmission performance, tyre specifications, steering systems, suspension type and performance characteristics, mass of the vehicle and weight distribution, Australia's transport lawmakers have recommended ESC vehicles not be modified in any of these areas.

The current edition of Vehicle Standards Bulletin 14, covering modifications to cars and 4WDs, has a critical clause (2.6) which states:

"Unless specifically permitted by the vehicle manufacturer, vehicles equipped with ESC as original equipment cannot be modified under the Modification Codes I contained in this Section of the National Code of Practice, as the current codes do not possess sufficient scope to account for all the parameters noted above.

"Similarly, vehicles equipped with electronic stability control (ESC) must not have the ESC control unit disconnected or modified."

The Australian Automotive Aftermarket Association is currently taking up this issue, which could affect common after-market vehicle changes, such as suspension upgrades and replacement wheels and tyres.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ESC = electronic stability control

I wonder if twin cabs will be included as "passenger carrying vehicles?"

PeterD

Member - Bucky replied:

Roachie

Not all seems to be right there,. Are you sure you got it right ?

Trucks have no Internal Mirror. See where I am coming from, and you have intended to make things safer by installing a camera. not too sure where that leaves people with caravans, and rear cameras too.

One area that concerns me with your 4B, is it's height above sea level. it's bloody high, and there would be some legal issues there.

Another area would definately be your weight, no not yours or Annette's, but the weight of the Patrol. It's bloody heavy, and one way which you may get it back to legal, would be to change the suspension, to suit it's rather heavyness. ( new word ! )
Dunno how you will ever be able to get an insurance claim, if you stack it..
Are you with Shannon's. ?
How many engineers do you know ?

Other than that ,,,,.... how are you ?

Cheers mate
Bucky