This confuses me a bit... My desire is to keep ride when unloaded the same by letting the air out (or near zero psi). Then when towing air up to maintain the rear ride height. The only real way to set this up right is to air them up (under load) until you achieve the original ride height (I think).
Maybe these aren't for us....
You can't have them without pressure. They have to have at least 10psi in them at all times. This is in the manual, it prevents excessive wear and tear by not letting them get pinched. These aren't load leveling airbags like on trucks. But I've found at 40psi which is 10psi over the max recommended limit on the bags even though I found a conflicting manual that said you could go to 50psi if there was less than 1" of space between the coils.
Since these airbags go inside the springs but don't go to the very bottom and very top of the spring they don't raise or lift the spring unless it's compressed to the point of the airbag. So you may get about an inch of sag even with the airbag. These airbags don't expand up and down, they expand out to the side putting pressure against the inside of the spring making it stiffer and more difficult to compress.
I have an air gauge/ compressor kit so I can air up or down the airbags on the fly and make sure the bags always have 10psi in them. I've found that if I fill them at 40psi, then hook up my trailer that has got to be at 400-500lbs of tongue weight the pressure will read 45psi and it rides very level.
I also haul a power chair lift and power chair from time to time. The combined weight of that is over 550lbs of dead hanging weight, I again run 40psi and the jeep sits fairly level.
First picture, with airbags. Second picture, with airbags, third picture without airbags. Fourth picture is of the undercarriage that you can see the airbags. I was on a 30 degree RTI ramp.
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