Airbag PSI Method

[timelinex]

I've got a 2020 3500 that I'm using to pull a 5th wheel that's about 19k LB with ~3k Pin Weight.

At the direction of the guys here I got some Timber Grove Airbags. Install was great and they seem to work exactly as intended.

I am having trouble figuring out how much PSI to use. I called the owner Steve at Timber Grove and it's pretty Amazon customer service that he personally picks up. He told me to measure something on the back and just get it back to that height....I confirmed with him if that meant "tail high" and not actually level and he said yes, back to stock height. At 80 PSI I'm not quite back to stock, but getting close. However the issue is that because of it being tail high the very rear of the bed is already only 5" away from the 5th wheel. I may call him again, but don't want to be a bother.

I am trailering later today. Any advice on figuring out a good PSI?

 

[davidh1329]

For me, my 2500 takes 60psi to get within 1/2 inch of stock height with about 2.2k on the pin. I've run slightly more and less on different trips and that "felt best". There is no exact pressure - everyone's mileage will vary. If you (and the truck) like 80, then you could adjust the hitch to gain more clearance.

 

[timelinex]

For me, my 2500 takes 60psi to get within 1/2 inch of stock height with about 2.2k on the pin. I've run slightly more and less on different trips and that "felt best". There is no exact pressure - everyone's mileage will vary. If you (and the truck) like 80, then you could adjust the hitch to gain more clearance.

How are you judging what felt best? What does too little feel like and what does too much feel like? I've got a manual pumped one so I unfortunately I can't just pump while riding.

Right now the trailer is about level, give or take 0.25 degrees or so. I can raise the hitch, but then the problem will be the trailer will be nose up by that same inch. Isn't riding nose up a worse issue? Especially when I am already having issues of being light on the pin weight (toy hauler).

 

[davidh1329]

I originally installed the airbags because my truck would occasionally hit the bumpers when driving over interstate bridge transitions. At first, I pumped them up until the truck moved back up to original height - I thought that "felt" a little bouncy, but it wouldn't hit the bumpers. Next trip, I added less air, but had it hit the bumpers again (less often). There are a couple of I-95 bridges in Georgia that my combo really doesn't like... Next trip, 60psi brought me within 1/2" of truck level and no bumper hits, so that is my setting for now. My Airlift system has a remote and a phone app that makes it easy to adjust pressure on the fly.

Nose high is not good because it can increase the loading of the rear axle. I am not sure with the new equalizer spring brackets if that is the worry it used to be. But, 0.25 degrees is likely not a big deal. I personally would be more worried about the bed clearance. Turning into my cul-de-sac really twists the truck/camper and at 5" would likely hit. I think I am a little over 6" now.

Did you install the air bags to improve the ride or to raise the back of the truck? The whole exercise of pulling a 5th wheel is a balancing act with ride/truck squat/bed clearance/trailer level.... you likely won't get all the parts perfect. I have a tad of squat and I think I am a little nose high on the camper.

 

[timelinex]

I originally installed the airbags because my truck would occasionally hit the bumpers when driving over interstate bridge transitions. At first, I pumped them up until the truck moved back up to original height - I thought that "felt" a little bouncy, but it wouldn't hit the bumpers. Next trip, I added less air, but had it hit the bumpers again (less often). There are a couple of I-95 bridges in Georgia that my combo really doesn't like... Next trip, 60psi brought me within 1/2" of truck level and no bumper hits, so that is my setting for now. My Airlift system has a remote and a phone app that makes it easy to adjust pressure on the fly.

Nose high is not good because it can increase the loading of the rear axle. I am not sure with the new equalizer spring brackets if that is the worry it used to be. But, 0.25 degrees is likely not a big deal. I personally would be more worried about the bed clearance. Turning into my cul-de-sac really twists the truck/camper and at 5" would likely hit. I think I am a little over 6" now.

Did you install the air bags to improve the ride or to raise the back of the truck? The whole exercise of pulling a 5th wheel is a balancing act with ride/truck squat/bed clearance/trailer level.... you likely won't get all the parts perfect. I have a tad of squat and I think I am a little nose high on the camper.

Well, the 0.25 degrees is BEFORE raising the hitch to the next hole. Raising it would put the nose of the trailer up 1.5" which is probably another 0.25 degrees. Not sure whats worse as I don't have the proper experience to know.

 

[davidh1329]

"...proper experience..." - good luck with that! I have been pulling 5th wheel campers for about 15 years and I am not there yet
Keep an eye on your tires - be careful around fuel pumps - don't yell at whoever is helping you back into a spot - have fun. Those are the big rules, the others we get the best we can. I, from (unknown) miles away, would let the truck squat some and keep an eye on the bed clearance. Adjust the hitch/pin box as needed.

 

[Surgdoc4]

I've got a 2020 3500 that I'm using to pull a 5th wheel that's about 19k LB with ~3k Pin Weight.

At the direction of the guys here I got some Timber Grove Airbags. Install was great and they seem to work exactly as intended.

I am having trouble figuring out how much PSI to use. I called the owner Steve at Timber Grove and it's pretty Amazon customer service that he personally picks up. He told me to measure something on the back and just get it back to that height....I confirmed with him if that meant "tail high" and not actually level and he said yes, back to stock height. At 80 PSI I'm not quite back to stock, but getting close. However the issue is that because of it being tail high the very rear of the bed is already only 5" away from the 5th wheel. I may call him again, but don't want to be a bother.

I am trailering later today. Any advice on figuring out a good PSI?

I put in Air Lift Liftloader 5000. Empty I run at 12#, with trailer put in 50#. See pic.

 

[Surgdoc4]

I put in Air Lift Liftloader 5000. Empty I run at 12#, with trailer put in 50#. See pic.View attachment 39147

Pin weight from specs says 3390. With 50# unloaded the air bag pressure with trailer is about 70#. I use the manual fill, didn’t trust the auto fill with electronic pump. Btw this is a 2500 Cummins.

 

[Surgdoc4]

Pin weight from specs says 3390. With 50# unloaded the air bag pressure with trailer is about 70#. I use the manual fill, didn’t trust the auto fill with electronic pump. Btw this is a 2500 Cummins.

Still waiting for my 3500 DRW to arrive but this will have to do for now.

 

[Scooter29]

I also have timber grove, and when pulling my 1600lbish tongue weight toy hauler I add air just till the overload spring is just starting to engage. This ensures that the suspension is still doing the work and your not just riding on the bags which can be bouncy. Won’t put the truck to stock but should still be enough to level it out.

 

[Brutal_HO]

I don't know why you wouldn't run the truck and trailer level.

If anything, maybe the truck rear 1/2-1" higher than level. FWIW, that's where unloaded height on a factory air truck sits and that's where it levels to unless using Alt Trailer Height, which drops it 1" to level..

A non air truck rear is going to sit ~3: higher than level unloaded. The suspension rides the best with some load.