Air spring pressures when towing

[EZeis]

Hello,

I have air-lift air bags and the wireless controller. When I hitch up my 5th wheel with about 1200 lbs of king pin weight, I air up to 45 PSI to level out the truck as per the instructions. Rides great but when I hit dips in the road or bridge joints, they bottom out. I need to air up to 65 PSI before they stop bottoming out and that seems like way more air than I should need for the light load.



Shocks are fine, no bouncing or floating. Truck bottoms out and comes right back with no boucing. Also less than 40k on shocks. I never bottomed out until I added these bags. I think they're limiting my suspension travel.



Other wise I love them. Any ideas? What if I load up with twice the weight? I'll hit the max 100 psi and run out of adjustment.



Thanks,

Earl

 

[NIsaacs]

Tow with the '93



What is the relaxed distance between the bottom mount and top mount? Empty truck with no air. I forget the minimum/maximum amount per the instructions but seems like about 6/7 inches? I would think any amount of air would be fine for what works as long as it stays under the max.



Nick

 

[Hoefler]

You are most likely not bottoming out. You probably are hitting the over loads.

 

[jelag]

We have air bags on several trucks... on my personal truck I've installed a simple bubble level like you'd use on a 5er... once the trailer is connected we just dial the air pressure to bring the truck back to the same height... . so that at night we're sending the head lights in the wrong direction... .

 

[Bill Stockard]

Yes, air bags do limit suspension travel. There was a long forum discussion about this in '03 or '04 after the 3rd generation trucks were being sold. On the 3rd generation trucks, the no drill/bolt on air bag systems for these trucks replaces the axle to frame jounce bumper. The compressed height of the air bag and its bottom bracket that mounts on the axle is more than the height of the factory jounce bumper. This increased height acts as a taller jounce bumper and bottoms out as if the factory jounce bumper was hitting the axle.



I know of one TDR member with a 3rd generation 3500 Single Rear Wheel (SRW) that had the same problem as you are having. He removed and sold the air bags and had an additional leaf added to the truck's standard spring set at a truck spring shop. This worked much better leveling his truck with king pin load of his 5th wheel trailer.



Bill

 

[EZeis]

You are most likely not bottoming out. You probably are hitting the over loads.

2500, I don't have overload springs.

 

[EZeis]

Yes, air bags do limit suspension travel. There was a long forum discussion about this in '03 or '04 after the 3rd generation trucks were being sold. On the 3rd generation trucks, the no drill/bolt on air bag systems for these trucks replaces the axle to frame jounce bumper. The compressed height of the air bag and its bottom bracket that mounts on the axle is more than the height of the factory jounce bumper. This increased height acts as a taller jounce bumper and bottoms out as if the factory jounce bumper was hitting the axle.



I know of one TDR member with a 3rd generation 3500 Single Rear Wheel (SRW) that had the same problem as you are having. He removed and sold the air bags and had an additional leaf added to the truck's standard spring set at a truck spring shop. This worked much better leveling his truck with king pin load of his 5th wheel trailer.



Bill

I figured as much when I was installing them. The truck is bottoming out on the bags. I guess I'll just keep runing pressure high enough to keep it from bottoming out. This sucks as the air bags make the truck ride better and handle better. Guess I'll just have to live with running higher pressure than I should be. I did email Air-Lift and I'm waiting to get a reply from them.



Earl

 

[EZeis]

Tow with the '93



What is the relaxed distance between the bottom mount and top mount? Empty truck with no air. I forget the minimum/maximum amount per the instructions but seems like about 6/7 inches? I would think any amount of air would be fine for what works as long as it stays under the max.



Nick

Believe the 2wd trucks have a min height to be maintained on the air bag at all times.



Earl