Air pressure in air bag suspension

[Nobby]

In the patrol I have purchased I have red poly airbags in the coil springs.
What pressure should I run them at
1. no load
2. medium load say 1/2 tonne - 1 tonne in trailer
3. heavier loads

Nobby

[timbar]

sorry mate i have no idea but im sure someone will have an answer for you soon

[YNOT]

The only thing I know about air assist springs is you should keep a minimum 5psi in them at all times to stop them getting pinched by the springs.

Tony

[my third 256]

hi i have them on mine and yes ynot is correct
the coils do the main work so the airbags are used to level the load so the ass doesn drag on the ground
when i tow the boat its at 22 psi / if used at this pressure unladen it looks like a wedge or funny car comming down the street
it is a matter of knowing approx what weight you are putting on
then remembering what pressure to put in
or you can just leave it at 18 psi as i do and only inflate for the reel heavy loads
hope this makes sence
stephen

[Bigrig]

Mine are flat as a tack when not being used ... oopsey ... lol

I honestly couldn't tell you what I pump them up to - I've only used them twice, and both times just pumped in air until they started to lift the back end and eyed it up from there!! I was in a rush though ... honest! lol. And that was prior to getting the lift, so might be something to play with on the weekend!

[Ghost]

also be aware over inflating with 2 much load can break the spring hangers off the chassis

[Bigrig]

also be aware over inflating with 2 much load can break the spring hangers off the chassis

Never thought you could over inflate them as such (other then rupturing them) - good tip, as I'm a bit ... let's say ... lazy!! lol ... when it comes to things like this!!

[Nobby]

also be aware over inflating with 2 much load can break the spring hangers off the chassis

How can you determine how much is too much pressure? i do move heavey loads at times up to max. pay load.
Nobby

[Silver]

Generally the red ones are Poly Airs, the blue ones Firestones from the Airbag Man etc.

Polyair used to state that the airbag had to be inflated before loading up the vehicle. I don't know if that is still the case.

The blue Firestones (which I have) can be inflated after loading up to get back to level again. From memory the Firestones were at max pressure when they protruded to half the thickness of the coils.

Min pressure on the Firestones is 5 psi. Max from memory is 30 on GQ patrols. I have never had mine above 20.

Apparently all airbags that work with coils or leaves reduce axle articulation. Haven't tested it, but it makes sense.

[the evil twin]

Me, I just "eyeball" the ride height but... Technically, the 'best' way is...

Let all the air out of the bags

With average load in the back measure the height front and rear of the vehicle (yes, front as well) use, say, the Bullbar and rear bumper, towbar, whatever to give you a ride height relationship of your particular suspension setup and lift etc. Remember that the vehicle is designed by Nissan to have some load in the back plus fuel etc and not be dead empty so if it is 'empty' maybe take a couple of mils off the measurement.

Put a couple of PSI in the bags. This is to inflate the bag and prevent possible pinching more than actually adjust the levelling the vehicle.

If the bum is dragging a bit due to draws or whatever you may need an extra couple of PSI (I run mine at 8 PSI due to a lot of accessories permenantly mounted in the back)

Whenever a large load is added (Cargo, Trailer, whatever) and the rear sags you should add air pressure until the vehicle ride height relationship is back to the measurement you got initially IE back is 'X' mm higher than front.

Now that sounds long and involved but it only takes a few minutes really and you only have to do it once to suss out for example
"Van on and back loaded for trip = 20 PSi,"
"Roof rack loaded and dual rear wheel carrier with both spares on = 15 PSI"

As I said, the other method is just wack in some Air till it looks right to the old Mark 1 eyeball.