Is it me…or do air bags really suck on a lightly loaded truck?

[deezuldon]

’06 2500 SRW 5.9L 4x2

I added a Pac Brake exhaust brake recently and it was a whopping success. Best addition I’ve ever made to any truck I’ve ever owned. Based on that success and wanting to level the truck with a 750# tongue weight and a 300# motorcycle in the bed, I added a set of Pac Brake air bags. I already had the on-board air, so it was a simple installation.

I recently towed 2,000+ miles with the load described above. The air bags did what they were supposed to do...leveled out the truck. Even with a load distributing hitch, the ride with the bags became a little “choppier”, but not to a particularly noticeable degree. All was fine in the world.

Got home, unloaded everything, and the truck rides like a pogo stick! It’ll even get air in the rear going over RR tracks. So I emailed Pac Brake. They suggested I could go down to 5 PSI (though it said 10 PSI minimum in the instructions). Tried that – and it helped, but it still rides like there’s a solid link between the frame and the rear axle.

Before I decided to go with the air bag suspension, I tried to find the old-fashioned air shocks that used to be around. I guess they’re still around, but there is no listing for our trucks, and it’s evident that Monroe and others don’t push the product very hard. So I went the air bag route.

I have a camper shell that weighs 425#, and with tools and other spares in storage in the rear, there’s probably 600# +/- on the bed all the time. Truck used to ride like a big station wagon (compared to my former ’99 2500) and it was a pleasant truck-like ride. Now it rides, empty, like a kid’s pogo stick. I’m threatening (in my mind) to remove the air bags, put ‘em on craigslist and either go back to stock and put up with the 1.5” of rear droop under load, or pursue the air shock idea a little further.

Is it me? Anyone else notice this downside to air bags? I don’t think it has anything to do with Pac Brake as a brand; their products seem to be top-notch. I think it’s just the nature of the beast, and no one brings this negative issue with a lightly loaded truck.

Opinions? Ideas? Experiences? Before I pull the air bags off and start over? Anybody have any good experience or advice to offer on the air shock idea?

https://www.turbodieselregister.com/images/smilies/confused.gif

Thanks in advance for the anticipated insight!

 

[AEdelheit]

Air bags build a ton of rebound force when they compress, custom valved shocks with extra rebound shims will help but cost more then the bags did. Nature of the beast unfourtunalty.

 

[Wertles]

I only noticed a slight difference with the air bags and I had 19.5 wheels on also. I also emptied the bags to zero when unloaded and had no ill effects in 4 years and 40,000 miles.

 

[JR]

They do ride rough but are worth the trade off IMO when running loaded. Lots of guys run ping tanks and claim it helps. I'm considering adding one, if I can come across a deal on an air tank that will fit my set up I'll probably try it but it doesn't bother me enough right now to buy a specific tank.

 

[deezuldon]

Ping tank? What is a ping tank?

 

[deezuldon]

OK. Figured it out. An accumulator tank or pressure compensation tank. Maybe it's the tiny 1/2 gal air tank that Pac Brake supplies with the exhaust brake? I've thought about upgrading to a 2.5 gal tank, and upgrading the compressor. Maybe at the same time, I can plumb in a "ping" (where did that name come from?) tank to each air bag...and maybe that will help? Or maybe one ping tank for both air bags, changing the system to balance pressures in both air bags. (Fill one, fills 'em both!) Food for thought. If it works!

 

[jelag]

I've got both a pacbrake and their air bag kit... I have to drop the pressure to 10 psi when empty to get any kind of ride... I have a regulator under the hood and when I tow I just add pressure to level it...

 

[ScottLewis]

I generally run 5# solo on my bags. When I drop the 5th wheel on it, pressure rises to 20#without adding more air. The ride empty is pretty good and loaded it rides fairly level. I can add more air if driving at night and my headlights appear to be blinding oncoming traffic.

 

[CBari]

I run my bags empty all the time over 100k miles on them with no ill affects. I have debated the ping tanks and doing a single tank for both bags after research I don't think that is the best way to go. Best I can tell is you want a minimum of 1gal tank for each bag with 2 1/2 gallon being the best. Now I haven't done this yet as I bought a 2014 and 2003 with the bags has become a farm truck with a flat bed on it the extra weight fixed it ride issue.

 

[BarryG]

another possible option to consider is the daystar cradle mounts http://www.daystarweb.com/productdetail.php?productID=1232 While I have not used them at least yet I am seriously considering them. I have a carli suspension with their rear leafs which are soft. Great empty/light load ride but when I hook up the trailer they go farther into the spring pack ie sag. Carli doesnt make a long travel air bag for my year of truck and they suggested the daystar cradles. They replace/ in addition to the bottom airbag mount with a cup and the bottom of the airbag is not attached to it, the bag is then allowed to lift. While this would certainly help with travel not sure if it would help the ride or not.

 

[AEdelheit]

The daystar cradles are neat but only help with droop, they will not help with compression rebound in any way unfourtuanlty.

 

[SnoKing]

What air pressure to you run in the rear tires empty. If you leave that pumped up for heavy loads it will never ride good when empty! I lower my rears to 42-44 empty. SNOKING

 

[deezuldon]

All good points and input - thank you to all! I am considering the pressure compensating tanks, but that just adds more complexity and cost. But in other forums and links elsewhere the "ping" tanks seemed to have helped others. Two people have now noted that they run 0 PSI in their bags and have had no ill effects, one @ 40K mi and CBari above @ 100K mi. I've tried that - and it definitely makes a difference. But I notice a strange "crease" in the bags, that I assume will eventually lead to deterioration at that crease. Snoking's point is well taken, but that's already factored in.
I'm just disappointed that it was never made note of by the manufacturer in application notes or installation instructions as a possibility - with tips to alleviate the pogo stick ride if it happens. I must be in the low percentile of those who don't keep a load on all the time! I have some ideas; I may try temporarily a couple long lengths of larger diameter hose (Maybe 1" x 7' - 8' long) before going the tanks to see if that reduces the pogo stick effect. Thinking along the lines of an accumulator tank in a water line to reduce/eliminate water hammer. Maybe that will help.

Anyway thanks again for all the input! (Interestingly no one poo-poo'ed the air shock idea or had any thoughts about that direction. Maybe I'm barking up the wrong tree on that one!)

 

[SnoKing]

You did not answer my question on rear tire air pressure????

 

[LandShark]

After unloading my slide-in camper I do 3 things to soften the ride. Reduce air bag pressure from 90 to 5psi, reset the adjustable shocks from level 5 to 1, and drop the tire pressure from 85 to 40psi.

 

[deezuldon]

I run 55 PSI in my tires, unloaded. All around. May go to 70-75 in the rear depending on the load, and up to 60-65 in the fronts. On my previous Dodge ('99) I ran Michelin LTX's and got nearly 100K mi per set. I also routinely ran them at 40 PSI unloaded until I noticed that later in the tire's lives, a wear pattern where the outsides, each side, (about equal to the rim width) were wearing faster than the rest of the tread. I went up to 50 PSI and in subsequent sets of tires, did not notice the uneven wear. And yes, I rotate the tires, typically about 10-12K on average.
On the newer truck ('06) I'm trying Cooper Discoverer H/Ts this time 'round. I had great results with Michis on my '99, but the Michis just got out of hand price-wise. So I searched around a found the Coopers (Made in the US!) at a much better price. Running 55 psi in those, and tread wear is even, so far. 'Course I only have about 25k on those so far, so won't know the full story for another (hopefully) 65-75K mi.
I know that if I air 'em down they will ride softer, but tire wear and possibly mileage may suffer. YMMV!
I don't mean to morph this thread into a tire discussion, as the intent is to discuss the air bag situation. But as Snoking notes, obviously tires can affect the ride.
Thanks -

 

[JRBurton]

I have the same on my truck. Run the air bags empty or just 5# of air. Love the air bags but the exhaust brake sucks *****.

John

 

[RustyJC]

I have the Firestone RideRite airbags on my truck. I run the bags at 35 psig for towing to level out the truck, and it rides just fine. Many times I won't air the bags down when I unhitch the 5th wheel, and the rear does get quite a bit choppier than stock when unloaded at 35 psig. At 5 psig, however, (Firestone's recommended minimum pressure), it rides very close to stock.

Rusty

 

[Cummins12V98]

I run 5psi empty and when hitched the pressure goes to 30psi. Makes no difference in ride height. Just controls the springs on really rough roads. At 5psi empty it rides the same as when I had no bags.

Rusty are you running 35 psi loaded or 35psi then add the load?

Pic is with 30psi in bags with load on. I have in cab controls. 4,500# pin weight.

 

[RustyJC]

Rusty are you running 35 psi loaded or 35psi then add the load?

I don't have an on-board compressor, so I'll run it 35 psig loaded or empty unless I bleed it down to 5 psig. It rides at pretty much the stock stance (a little tall in the rear) with the MS hitched up which keeps the headlights aimed correctly, but unhitched with 35 psig it's about 2-3" higher than stock in the rear when unloaded.

Rusty