What air bag pressure to run?

[IWeiny]

I have a 2500 HD 4x4 with the overload springs. We just put a camper on which weights 3100# (real wet weight based on weighing it)



I have thought that the truck rides better with only 50# pressure but it also seems to ride well with 70#. 60# seems to sway bad.



The problem is that 50# seems to be right almost on the overload springs where 70# seems like there is no load on the truck, basically stock height!!!



I would kind of like to run with only 50# because it really seems to ride better but I am worried about destroying the regular springs with it riding so close to the overload springs.



Any thoughts on the pressure I should run with this load?



Thanks,

Ira

 

[ProspectorTim]

I'm not an expert, but in MY opinion ...



You should adjust the airbags to set the truck at or close to the "normal" ride height to keep the headlights pointing down the road instead of in the sky or the eyes of oncoming drivers. This will also keep your steering geometry correct and probably be best for aerodynamics.



Be aware that these trucks also have a front-to-rear brake proportioning valve that is affected by ride height. It is normally setup to provide light braking to the rear when unloaded (high ride height) and more rear braking bias when loaded (low ride height). Now that you got me thinking about it, I guess we need to look into an adjustment for that linkage (or disconnect it?), to provide the heavier braking when airbags bring the suspension up to "normal" ride height even though the truck is loaded.



I look forward to seeing other folks opinions on this topic!

 

[BigMike]

I usually have 60# in mine with about 5700lbs on the rear axle. You're probably heavier than that. I don't notice a difference in driving no matter how much pressure I have. I'm pulling a 5er. I adjust mine until my truck sits level with my tow. That way, I'm not pointing my headlights into the eyes of oncoming drivers. It's a great setup for my situation.

 

[MGordon]

I set mine at 90psi. This gets the truck almost to normal ride height.



I would like to know more about the braking issue. If raising the load is keeping the rear brakes from doing more of the work thats probably not a good thing.

 

[IWeiny]

Pulled the ride height arm

I already pulled the arm off and have the valve up in the "fully loaded" position.



I already thought about that but I am really feeling a difference in the sway of the truck. I have about 6000# on the rear axle. Depending if I have the trailer or not and how the weight distribution is set up.



I guess now that I think about it 3000# per bag would be about 6000#. And 3000# is just under 100psi... I was thinking that the truck would only have about 3000# of load back there since that is what the camper weights?



I never though about the headlights but even at 50# the truck is sitting higher in the rear than the front. I will just have to play with it some more to see how much it is going down.



When I first drove the truck back from the dealer they had only put 30# in them!!! But this was on the overload springs so I really don't want to run that low.



Anyway, thanks for the opinions.

Ira

 

[ProspectorTim]

Re: Pulled the ride height arm

Originally posted by IWeiny

When I first drove the truck back from the dealer they had only put 30# in them!!!

I installed my own AirLift bags, and one of the first instructions was to measure the "stock" ride height and write it down in the owner's guide before installing the airbags.

Thier recommendation was to put in enough air to return the truck to that height.

 

[MHalberstadt]

I have a 97 SLT 2500HD. While we have a fifth wheel now we used the camper the first 3 years we had the truck. It was a Fleetwood Caribou 10ft. So roughly 4000 lbs. I ran the air bags a 55psi both sides. I got there by just measuring the level of the bumper unloaded then aired the bags intil the measurement was the same loaded. I messed around between 30 and 80 lbs but 55 was best comprimise between steering and ride. I would adjust both sides on ocassion when we would go on a longer trip my wife would load the bunk over the dinette with food and supplies to the extent that I had to put 90 in one side to get the truck level side to side. Still have the truck and run 25 psi when we have our 31 ft. fifth wheel hooked up.

 

[rrl989]

Ira,



Seemed to take me years of experimenting. I did discover that with the pressure too low, I really twisted and bent my bottom air bag mounts because they will bottom out. Found that 90+lbs. pressure kept my ride height too high but gave the best ride with slide-on. Had my bags mounted on top of the overload springs, best use would have been to use one or the other and not both.

Ended up removing the bags.



Ron