Air bags vs. Helper springs on Chevy Astro

[Gary Little]

Well I finely found me a real nice 2000 Chevy Astro passenger van with the 3.73 rear end. The van is in excellent condition and I love it. I will probably travel with the rear seats remove (approx. 150lbs each) to help with the added tongue weight. But if the rear still needs some extra support which would give me the best results air bags or helper springs added to the leafs.

Thanks,
Gary Little

[Benita]

My Safari has air bags. Big improvement. I like the overall extra lift.

[CD Smith]

I have used Air Bags (1970 Oldsmabile Vista Cruiser and 1966 Corvair) and Air Shocks (1984 Chevrolet Caprice, 2001 Cadillac DeVille, 2004 Cadilac Escalade).

I found the Air Shocks to have the most comfortable ride. The two Cadilacs were (are) self leveling, but the Chevrolet was easy to level by adding air at the fitting mounted just to one side of the tag.

If I had to choose between the three approaches, the Air Shocks would get my vote.

[Kurt & Ann K.]

Gary,
What size Scamp? Would a weight distribution hitch be an alternative?
It would leave the tug as the manufacturer designed.
Just another thought.

Kurt & Ann K.

[Pete Dumbleton]

Be aware that none of the three (air bags [aka air springs], overload springs or air shocks) will actually do anything but jack up the rear of the body and also create a better ride under load -- They do NOT level the suspension or change the load capacity -- If your front wheels are too light without spring assistance, they will be too light with spring assistance because no weight is transferred to the front (like with a WDH).

Anyone with air bags who doesn't believe this should put the front axle on a scale and then raise and lower the rear bag pressure and see how much the scale does or doesn't change.

I had air bags on my 82 D150, but they turned out to be overkill -- Just a little pressure put the body back to level and even the slightest leakdown would have it sagging (and it is bad to run them empty because the bags get damaged -- OTOH, if the vehicle is to be jacked up, the bags MUST be emptied or they may be damaged, so you have to be careful to remind service folks of this) -- The overkill might not be so bad if the bags are designed for a particular vehicle; my setup was designed to fit a number of trucks and mine was probably on the light end of the range.

If I were going to do it over, I would get the overload springs (aka helper springs) because they cost far less, can't leak and are less likely to have any sort of problem -- Additionally, because most only come into play when under load, require no adjustment for heavy or light load.

I've had air shocks in the past and found them to be effective, but with all the air bag problem potential listed above, plus the air shocks mount to a far less robust fitting than do the air bags/overload springs -- Wnen I removed an old set of air shocks from my truck, I found the mounting stud on the axle was bent significantly...

[Per Walthinsen]

Our Odyssey has air bags. Did what I wanted them to which was to return the rear suspension to normal height (independent rear suspension has more issues with camber and tire wear when compressed). Ride is better with trailer attached, headlights don't blind anyone, and control is improved. I did find that attaching the on-board compressor/gauge with dash controls made the whole thing much more user-friendly and it has other uses than just leveling the van. I run them at 5 lbs of pressure normally and about 30 lbs with the trailer hooked up. I did calculate what it subtracted from the weight on the front end, but the rear axle is so close to the hitch that the difference is nominal.

[CD Smith]

One additional note about air shocks/bags.

If you use them, they must be used to level your TV after the TV is loaded and before you hitch-up you RV.

The WDH is used only to compensate for the hitch weight, not the 'stuff' you add to your TV.

[Brian B-P]

Pete's points about the limitations of add-on springsare valid and appreciated as always... but if the rear axle is within load capacity and just needs more spring height and stiffness, I would certainly add air springs. I added air bags to my Sienna, and am very pleased with the result. By the way, the change in front ride height due to trailer load on my van is very slight - I certainly can level the van by adding air to the bags. This depends on the specific vehicle.

Changing the springs may be changing the tug from what the manufacturer designed, but linking it with sticky springs to a trailer (which is what a WDH does), is at least as significant a modification. Neither should be undertaken lightly.

The advantages to me of adding air bags to the coils (which would be full air springs on the leaf-sprung Astro), compared to a fixed spring (like a helper leaf in the Astro) are

• they can be adjusted, to suit loaded versus unloaded conditions
• they are effective at the desired ride height, not just when the suspension compresses enough to bring them into play.

[Loren G. Hedahl]

On my pickup, I added leaf type overloads. These have a shackle at each end that you can adjust for load. They work just fine, except you can get a bit dirty doing the adjustment.

For the Jimmy I went with air bags. Since the rear suspension was excessively stiff to begin with, I removed 3 of the 5 original leaf springs first. Now unloaded, it works well with about 20 psi and up to 80 with a load. This system also works well, in fact the ride is quite a bit smoother. It has been installed for about 8 years and hasn't been plauged with leaks yet.