How much air pressure are air bags gonna need?

[CentralCoaster]

I'm buying some guages and tubing for my 1500 lb Firestone bags.

What sort of pressures are normal for these? Is a 100 psi guage plenty?

[bayer20]

Both my gauges are 160psi I run 75-80 psi in the front, 35-40 in the back and 135-140 for the tank. It will depend what pressure swith you will have installed. 135psi is min. hope this will help you.

[CentralCoaster]

I'm not using an onboard compressor.

I presume it take a certain amount of air to hold the ass end up, your pressure switch can be anything as long as its higher than that.

I was under the impression I could add air using a gas station compressor. I guess I'll be okay for the rear, but at ~100 psi for fronts that might not work if I decide to add front bags later. They probably don't have much more than that in their tanks, it already takes long enough to fill tires at 40 psi.


I'll get 100 psi guages. In fact, I'll just put one gage, one fill port, and 3 valves for the back. Then I can fill them up at the same time, and valve them out to check pressures seperately and to keep them from transferring air.

[Alvin]

Using the little electric compressors that take quarters probably won't work. Look at gas stations that have full size car washes. There's a shell station near here that has a real air hose running out of the car wash. Inflates my portable air tank over 100psi.

[CentralCoaster]

Originally Posted by Alvin

Using the little electric compressors that take quarters probably won't work..

Seems like they'd work for the rear, if it only needs 40ish lbs. The volume is way smaller than the tire. Hell I can use a bike pump to put 60 psi in there.

I think I'm more lost now than before I started. Oh well, I'm going ot go ahead and order the stuff anyways.

[67Fleet]

take a look in the suspension forum and use the search button. Your answers are in there.

[st1x10]

Before you buy the stuff look into it some more. Might check out the suspension forum. It can be confusing at times, but the more you know the better purchase you will make.

[CentralCoaster]

Nevermind. I spent 25 seconds thinking about it and realize 50 psi is a ballpark number for rear bag pressure.

Less than 1500 lbs on each rear corner with the bed loaded up, airbag is about the size of a roll of duct tape, 6inches across, that's 27 sq inches, 1500 lbs / 27 sq in = 50 psi


The fronts must be pretty small bags to require a bunch more pressure.

If it doesn't work out I'll come back and ***** and moan about my own inability to pay attention.

[Shane]

the fronts are actually larger than the rears ... that is, if you are running 2600 lb bags up front and the 2400 lb bags at the rear

[lowrollin70gmc]

The front also has a different leverage effect, as the rear is also not a direct 1 to 1 system.

[cajundragger]

also your math is off...1500 is the load rating of the bag at 100psi or whatever its load rated at. And the 27 square inches is off because you need the cubic volume measurement of the bag at your deisred height not the area.

Anyways, get 150psi to 200 psi gauges.

[jimmydean]

I used 150 psi gauges and rolled an average of 50psi front and 35psi rear.

The most I ever had was 80psi front (full lift) and 100psi rear with 1000lbs of hay in the bed.


<edit>If I didn't have a compressor, I would for sure carry a high pressure bike pump just in case. My bike pump goes to 120psi, but it might take a while. You never know when you will need to add pressure, but it's your call.