So mushy at lower ride height and stiff when raised. This sounds perfect for my GMC savana that could use a 4" drop for normal cruising and back up to normal ride height for six passengers and a 6000 lb trailer. Would this really work? Right now it is way too stiff until I get at least 1000 lbs of people in it, and my kids are not that big yet.
I've always wondered how well the shocks work with air ride since you have a wide range of theoretical spring rates. Are they gas charged shocks tied in to the rest of the system so that the shocks adjust with the bags? Or maybe they shoot for damping in the middle of the operating range of the bags?
The air ride setup on my Envoy works great. Did have to replace the bags at 60K but popped for upgraded units that were still 1/2 the price of the factory parts. Have been awesome for 80K in the snowy midwest. I wonder if you can't do some measurements to see what the closes cheap OEM setup is? Arnott
I figured I'd zombie my own air suspension thread as opposed to starting a new one.
I'm looking at taking my b2000 off the road for a little while to do some drive line work, and while it's off the road, am seriously considering fitting rear air bags while I'm at it.
I'm currently thinking of doing a trailing arm set up using the leaf spring mounts, either as a take on truck arms or adding a 3rd link on the top side of the diff. Bags would be mounted behind the diff using bag behind axle brackets. Shocks would be behind axle also, along with a Panhard rod and possibly a rear sway bar.
Ultimately, the b2000 will need to retain its utility function, but I'd like it to ride a little nicer and handle a bit better. That said, I know that what I'm trying to achieve will be full of compromises and I'm ok with that.
I'm not really looking to have massive adjustability in ride height, more the ability to maintain the ride height when loaded or the ability to air out when parked because well, "I'm a cool stance bro yo!"....
I'd love to go a more traditional truck arm setup in the rear, but fuel tank location pretty much rules that out. This guy did similar to what I'm thinking, but I'd be using bags as opposed to coil overs
http://projects10.freeservers.com/coiloverrear.html
As for the front end, I haven't thought to much about it yet, but would like to improve the front setup over the stock torsion bars. Options include coilovers, stiffer front torsion bars or air bags. To be honest, I'd probably prefer coilovers, but don't know how they would respond to putting a load of stuff in the tub? I'm assuming they'd deal with it ok but I'm no suspension guru.
mazdeuce wrote: The idea behind performance air suspension is to make it work very very well at one ride height.
^This.
First, set ride height.
Second, select air bag, or air spring that is rated for the planned load. Since you've already got parts, I'd say skip this part. Maybe heavier rated bags in back since this is a truck? Maybe in the front, because that's where the engine is?
Third, build, or mount "cups"-bag mounts, whatever.The big thing is bags have an operating range. Say fully extended is 6", 3"-4" is the operating range, 1"-3" is "slammed", etc. So, with say the rear axle at ride height, you want maybe 3-1/2" space between mounts for the air bag to fit in. When I was researching all this, I considered making a couple of dummy bags out of steel pipe (in this example, 3-1/2" long) to build the bag mounting points, without fear of burning holes in them. My feeling is that for instance, the cup measurement was 2" when you were on your bump stop, no harm, no foul. Again, you are working for a nice spring rate at ride height. You can jack the back up to carry a load of gravel, or whatever. Jack it all up to stiff mode to get up a crappy driveway.
All the physics that are applicable to regular coil springs are still true. You have lever effect if for instance, you use truck arms, and mount the bag on it, between the pivot and axle. That could get you more travel, but would complicate the math used to determine spring rates.
The above is a somewhat researched opinion, and should be treated as such. All in all, air bags look like a pretty forgiving, neat way to lower a street driven vehicle. I think it would be especially nice on a dual purpose truck. Best of luck.
In reply to wheelsmithy:
Yeah, I'm pretty much looking to pick and stick regarding the ride height for the bulk of the time.
I've got a pair of air lift dominator 2600's and a pair of 2500's. They'll be ample for what I want to do and get some pretty good raps from guys into air ride. Given they both mount pretty much the same, I can swap out the 2600's if I find them to firm.
I'd love to bag on arm, but simply don't have the space to make it work effectively. So I'll have to run bag behind axle, pretty much using this setup.
Best part of the bag behind setup is that it'll keep everything below the bed and nice and neat.
Though using the above mounting configuration leaves me wondering how and where to locate my shocks. I've seen pan hard rods basically mounted on top the diff when running bag behind and it looks to work ok.
What I need to work out, is wether or not a 2 link type setup utilising the original leaf spring mounts will work, or wether I'd be better off using the leaf spring mounts as part of a 3 link. A triangulated 4 link would be preferable, but I don't think I've got the space to triangulate the upper arms.
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