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With something like a Bilstein 7100 series damper you can change the shim stack to change the valving. I had to do this on the rear of my '84 Xcab when I swapped to 63" long GM 3/4t rear springs. Not because of a different spring rate, but because those springs have enough less internal friction to show up in the overall damping. Numerically the change wasn't much, from 255/70 shims to 278/75 shims but the difference in how the truck behaved was noticeable. These numbers are the force in Newtons need to move the shaft at one particular shock shaft velocity. Rebound first, Compression second.
With two different spring types, say leafs and air, you'll never get the damping very close. Each type of spring has unique needs in damping. As an example, in the 7100 series the std. off the shelf shim stack for leaf springs is 255/70. The std. off the shelf shim stack for coil springs is 360/80. One shim stack that I've seen for torsion bars was 345/135. I've no idea what air springs would want to start at, but I'd guess something close to coil springs. None other than Brett King, of King Shocks, told a good friend and savvy suspension tuner not to combine different spring types as he'd never make it work well in a serious Pre-runner style truck.
That said, I doubt many will want to abuse their campers hard enough to need that tight of a suspension tune.
I've seen air springs fail off road. I've seen them live and excel off road. It's dependent on the whole package; how are they driven, how were they installed, where were they installed (on the vehicle and by whom), what quality were they to start with, what kind of maintenance have they received since.
With two different spring types, say leafs and air, you'll never get the damping very close. Each type of spring has unique needs in damping. As an example, in the 7100 series the std. off the shelf shim stack for leaf springs is 255/70. The std. off the shelf shim stack for coil springs is 360/80. One shim stack that I've seen for torsion bars was 345/135. I've no idea what air springs would want to start at, but I'd guess something close to coil springs. None other than Brett King, of King Shocks, told a good friend and savvy suspension tuner not to combine different spring types as he'd never make it work well in a serious Pre-runner style truck.
That said, I doubt many will want to abuse their campers hard enough to need that tight of a suspension tune.
I've seen air springs fail off road. I've seen them live and excel off road. It's dependent on the whole package; how are they driven, how were they installed, where were they installed (on the vehicle and by whom), what quality were they to start with, what kind of maintenance have they received since.