Air bag suspension itself I'd fine.. It's the design, strength, axle location etc .. I have built the odd car Trailer carrier with bags so it can be lowered to drive car on.. Make sure frame is strong where it's attached.. Compared to leaf springs..
Same with bag assist in light trucks ..

I have air bags, independent in a single axle type arrangement (if that makes sense). Worth twice what I paid for it. Side to side leveling is a breeze and front to back gets some help. Corrugations seem to disappear. Just remember that bags get harder as compression comes on so there is room for argument if towing around corners above 150KPH. I have Firestone brand bags and have done about 7,500 in the dirt. What sort of problems frequently come with the setup you are looking at?

Iza

I am glad that someone has come up with this topic. I have been trying to get info on air suspension for a while now, but got nowhere. My problem is that I would like new poptop caravan which must fit into my shed. Doorway 2.3 m high, so to compensate for slight change of gradient on way in, I need a travel height of 2.25 m max. Then, I have to clear the driveway crossing into the street, so I need a good ground clearance. To me, adjustable air suspension seems the answer. Then you have the benefit of a much smoother ride for your van. My current van is a 1999 Jayco poptop which clears the doorway quite well, but scrapes its bum on the driveway crossing.

Now to the questions...
1 Alignment problems: Assuming independant suspension, I cannot see any more problems with air suspension over conventional springs. Assuming they are separate air supplies, if one bag leaks, you would obviously finish up with a leaning van, and due to possible camber change, maybe it may cause it to crab a little. What else can go wrong?

2 Air Leakage: I assume that the air bags will eventually leak air from somewhere. If they do, when the van was set up for camping, the stabilisers would finish up bearing a much higher load than possibly they were designed for. Can the stabilisers take the full weight of a varavan or are they merely stabilisers?

3 Bump stops: Do air suspensions have bump stops? I assume that they must, because without them there could be a lot of damage when the bags lose their air.

4 Automatic Restoration of Ride Height: To top up the air whilst travelling should not be a huge problem. My old Citroen DS21 had this facility. When a load was placed in the vehicle, front and rear sensors decided if more oil should be added to the appropriate end and suspension height was restored. If the vehicle was unloaded, it used to dump excess oil and the carwould sink back to its pre-set height. For a van air suspension, I imagine that a small compressed air tank and 12V compressor would be needed to maintain automatic ride height control. Changing the pre-set height would be relatively easy with a knob on the side or front of the van, connected to a valve. DO existing air systems have anything like this form of control?

5 Ability to kneel: My wife complains whenever we park facing downhill, because to level the van means that the step on the doorway is too high. If we could lower the to a park height, it would make for easier access and egress. Also, the ability to jack up the van to change a tyre would be enhanced with adjustable suspension. Do existing commercial air systems allow for the van to have adjustable heights for differing reasons?

6 Dynamic Stability: Because the air suspension is relatively soft, is there a tendency for the van to develop a swaying action? By this, I don't mean fishtailing, but rather a side to side rocking as the van moves along. I know that dampers (shock absorbers) should damp that sort of motion out, but has anyone experienced this?

7 Cost: Does anyone know how much the air system costs, compared to a standard spring setup? People have said to me it costs heaps more, but in the overall big picture of getting a new van built to specifications, is the extra cost that significant?


I'll put my hard hat on now so you can all throw brickbats at me, but any comments on the above would be welcom.

Kits are quite are well priced . You need to fabricate brackets and add some strength to some areas depending on what model etc .. It's not the bags themselves that may cause issues . You can't blame bags for bad suspension, geometry . I buy my bags ex US . Exchange rate at present doesn't help ..

Izabarack wrote:

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I have air bag suspension from Vehicle Components. Alignment procedure is quick and easy and documented on their site. Onboard compressor with a small holding tank maintains set pressure. Control switches for each side let me put one side up or down at will. Never had the problem but busted bags just result in things sitting on the bump stops until repairs. I have let bags down to flat to get under trees and branches. I have also pumped them up to max to get through spoon drains without scrapping the rear.

I have twin shocks each side and reckon the van rocks less than one with conventional leaf springs. I paid a lot of attention to where the weight is in my van, tanks and batteries very close to the axle line, and have had no sway problems.

I know my system was at the costly end of the range.

Iza

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Sounds like a very good rig. I hope we meet somewhere/sometime I'd love to see it.

We have Firestones on rear of LC79 series Ute, they never loose pressure even at the low 5-7psi I run them, which I found amazing.