this is going to be a 2 part question. i had the airbags installed a couple months ago. at install they aired them up for me so i didn't think much of it.

last night i dropped the pressure in the bags to 5lbs, but now am camping this weekend and pulling a 30' trailer.

is it best to air them up to 35lbs prior to hooking up the trailer, or do i load the trailer then air them up?

also, the first and 2nd tow i did with the trailer the airbags were sensational, really limited droop as opposed to when there were no bags.

however i pulled the camper home last night, and while there was 20-25lbs of pressure in the bags, the droop was basically as if they weren't installed.

something seem unusual about that?

 

Always air them up BEFORE putting any load on them. This allows the bag to properly seat inside the spring before taking any weight. The max air pressure in these bags is supposed to be 30psi. Did you maybe have more tongue weight than before? I know I usually have to go and inspect the under the bed storage before I hook up. My wife likes to put all the heavy things like pop/beer/water under the bed out of the way, but it puts too much weight on the tongue. Some other things might be water or waste in the holding tanks. My camper is 31' and 8700lbs DRY. Right up there at the max for these trucks so I like to tow with all the tanks empty.

 

we've had it stored for a couple weeks, the thing should be empty, i don't know if the psi was just lower than previous. i let dropped psi to 5lbs last night so i can start from scratch.

so i can put 30lbs of air in prior to loading the trailer? and at that stage the bags do the work?

i know, this all sounds very n00b, but to me they kind of are.

thanks.

 

I leave my Air Lifts at 10# all the time for normal driving. I'd be inclined to air them up before putting on a load and then adjust them to be perfectly level if need be.

I do this when pulling a trailer, but don't when I load my ATV in the back. With my lift height, my ramps are at a pretty severe angle as it is and I find I have to lean all my weight forward, over the handle bars if I don't wanna get the feeling that the thing is going to flip on the way up. At least with the bags low, I will get a little sag as I drive up. It would be pretty hairy if I loaded up with 35# in them.

I wouldn't even need the bags inflated for the ATV, but with my toolbox, almost all the weight of the ATV (700#) sits behind the rear axle and it will have the front end sticking up where my low beams are pointed to the sky...

 

i think the max is 35 ... but yes it does seem to work a lot better on mine as well if i air them up before applying the load. i usually do that, unless i forget and then have to air them up after. i usually run about 7-10 lbs normally, i think the manual said to run at least 5. to keep their shape.

 

i guess my question becomes this.

if you air them to 30psi, then drop the trailer weight on, doesn't that give the psi a pretty big hike?

 

Of course I've got different bags, not only different brand but I've got leaf springs, and these bags will take up to 100 PSI, but I've never found the PSI to change whether I have no load or load. Obviously, the pressure exerted on the bags from the outside increases, but I think the air pressure inside the bag would remain a constant...

 

Thanks for the replies.

Helps a lot.

 

The psi will not increase with load. It says right in the instructions to fill the bags BEFORE loading any weight into the truck. You have the right idea, to let some air out if needed after the load is on, but I have never had to let any out. I leave about 10-15psi in mine all the time, then put 30psi in if I load the atv/sled/camper. Be carefull, these bags inflate very quickly. I have the Air Lifts, and have heard of quite a few Firestone bags blowing out. I have installed both on different vehicles and they seem to be very similar construction, so I wonder if the 35psi that Firestone says may be too much??? I know that the Airlifts call for 30psi MAX.

 

Ok im just trying to figure out why the pressure doesn't change when you put a load on your truck. Don't the rear springs compress and put pressure on the airbags? If the rear springs compress and put pressure on the airbags then you have decreased the volume of the bags and by doing so you have caused the air pressure inside the bags to increase. So saying that the psi does not change with a load is false. Airlift says not to put more than 30 psi in their bags with no load so that they will be able to handle the higher pressures that they will be under when you put a load on your truck without exploding.