Thread: Firestone/polyair bags

Get an Airlift kit. They are better and have the lower protection pieces.

They do push top and bottom. That is how they work.

Originally Posted by steveG

Be aware that they aren't an air spring, more like a device to increase the spring rate. IIRC they're working by getting between the coils rather than pushing on the top and bottom like an air spring.
Been a while since i played around with pressures when I fitted them to the county, but from memory they tended to settle at their happy height after a bit of a drive - not necessarily the same height they were when first setting off.
These days I just put 25psi in them when fully loaded or towing the van, and about 4psi when not.

Steve

The operation here is correct but they do give a bit of a push also.

30psi for mine basically stops the springs working! I only put a few psi in maybe 10 tops when using and I run no air in them when not being used despite recommendations - so far no issues in probably 15years of them being installed.