Member - Jack replied:

I think the best idea is to load your vehicle up then pump the airbags until you have the vehicle level. No idea what pis that might come in at, but as levelling the vehicle is the intended purpose of the bags, that is where I would start.

I had the Firestone ones and that was how I worked it.

Jack

Member - Duncs replied:

John,

I had polyairs in my old GQ and teh system of loading the vehicle and then levelling it using the bags is what was recommended to me.

While I never did the Simpson with them I did travel extensively including Cape York and the desert parks of NW Victoria and had no problems with the polyairs using that system. I have done the Simpson in the GU and without the polyairs and wished I could have got the tail of my car a little higher. Poly's would have been nice.

If you got any litterature when you purchasd the polys it should suggest a max psi.

Duncs

uncle replied:

Hi there John,we gave our new Polyairs a test 2 weeks ago,on a trip into Bendethera.We had the Pajero fully loaded and ran 14 psi,with OME shocks all round and went superbly.I reckon that 20 in your cruiser would be about right,depending on the suspension set up.Cheers and all the best on your journey.

Trekkie replied:

We did the Simpson this time last year. I had Polyairs on 100 series TD towing a Kimberly - No problems at all - Used around 20 to 25 psi. Interesting that I fitted the Polyairs on recommendation of Service Manager at a Toyota Dealer.

My mate in an 80 Series also with a Kimberley had all sorts of problems on the Simpson even with modified suspension. When we got to Bundaberg, he fitted Polyairs and has never had a problem since (Cape York etc)

Polair specifically say NOT to inflate with a load. Pump them up first. Also always maintain at least 5 psi.

Member - Jiarna (NT) replied:

Hi

We just crossed the Simpson twice. 20psi in the air bags, and 18psi in the tyres, worked fine on our 80 series.

Cheers
John

Member - Cocka replied:

Morn'n JT

Everyones loaded weight will be different, also the load spread.
In general running adound mode measure up to the wheel arch from the bottom edge of tyre rim on the rear wheels. Note the measure.
Load up with air bags low pressure. Now pump up bags until you get back to measured height again.
The main purpose of PAB's is to keep vehicle level - then the headlights will remain focused at the level where they are meant to be.

The big tyres are the real pressure issue in the desert & stoney country.

Member - Banjo The First (SA) replied:

Here's the good oil from Airlift on the the www.truckspring.com site.....
Operation
1. Inflate the air springs to 35 p.s.i. before adding the payload. After vehicle is loaded, adjust the air pressure down to level the
vehicle for ride comfort.
2. When carrying a payload, it will be useful to increase the tire pressure in proportion to any overload condition. A 2 p.s.i.
increase above normal is recommended (do not exceed manufacturer’s maximum) for each 100 lbs of load on the axle.
See http://www.truckspring.com/airsprings/airlift/instruc/MN-133.pdf
Makes sense to me - in my view, expecting the bags to push up a big load with 35psi is vastly different to 'conditioning the springing' with the blown/moulded bags first, and then letting the load down onto the spring/bag combo.