Air suspension for adjustable ride height

[Taylor95]

Would these replace the coils on a car that is set up that way? Some of the ones I've seen seem to work in conjunction with the stock suspension system.

[JulianEdgar]

Originally Posted by Taylor95

Would these replace the coils on a car that is set up that way? Some of the ones I've seen seem to work in conjunction with the stock suspension system.

Yes these are 'proper' air springs, not just squishy bags (that fit inside coils) or donuts (that have a terribly fast increase in spring rate with compression). So these air springs completely replace the coils.

Rolling lobe air springs (like the ones I use) are the same design approach as used in Mercedes, Porsche, Tesla, Audi, Range Rover, etc.

There's a huge amount of poor information around about aftermarket air suspension. For example, many aftermarket air spring manufacturers don't even have load/deflection specs available! Many people also believe that air suspension is just for when you want to dump your car into the weeds, not get best ride / handling / aero.

As is almost always the case, original equipment manufacturers do it well, so you won't go far wrong if you look at what they do.

[Taylor95]

I would say that having poor information regarding air struts is an understatement.

Where did you find the specs for the struts that you have? I cannot find anything on that website regarding weight capacity, spring rate, or inches of travel/lift.

They have 10 universal kits, and so far the only difference I am seeing between them is the weight of the set. Their manual doesn't seem to include any extra details regarding specifications either.

[skyking]

Kelderman makes parts for my 2007 3500 SRW Ram. Pricey, but I can fab my own 4 link, and just buy their front systems.
https://kelderman.com/shop/?vehicle_...hicle_model=47

[JulianEdgar]

Originally Posted by Taylor95

I would say that having poor information regarding air struts is an understatement.

Where did you find the specs for the struts that you have? I cannot find anything on that website regarding weight capacity, spring rate, or inches of travel/lift.

They have 10 universal kits, and so far the only difference I am seeing between them is the weight of the set. Their manual doesn't seem to include any extra details regarding specifications either.

Yep, welcome to the world of aftermarket air suspension.

Airlift don't have any proper specs available, and when I asked them for some, they told me that it was impossible to provide specs, because air springs don't work that way.

I then sent them a specs sheet from the Firestone air spring catalog (below)....



...and then Airlift simply stopped communicating with me.

So I was able to design the rear suspension properly (I used Firestone air springs) but had to just guess with the front struts. They proved too high in spring rate, and so I added parallel reservoirs to soften their rate. (But even that was made difficult, because Airlift use too small an air fitting to allow this to work as well as it could, and you cannot enlarge the fitting easily.)

My book covers stuff in more detail than I have seen elsewhere, but it is just a little book (if I ever do a second edition, I'll enlarge it a lot).

[JulianEdgar]

Originally Posted by skyking

Kelderman makes parts for my 2007 3500 SRW Ram. Pricey, but I can fab my own 4 link, and just buy their front systems.
https://kelderman.com/shop/?vehicle_...hicle_model=47

I am not familiar with the truck but if it doesn't use struts then have a close look at Firestone's air spring catalog. I use Firestone springs on the back of my Insight - they have enough specs available to do a proper design. The catalog can be tricky to find - it's sometimes called their industrial catalog I think. My air suspension book covers the selection of air springs where there are spring specs available.

[JulianEdgar]

My first air suspension vehicle, during testing about 13 years ago. Not very good aero but incredible ride comfort and good handling.

[skyking]

Originally Posted by JulianEdgar

I am not familiar with the truck but if it doesn't use struts then have a close look at Firestone's air spring catalog. I use Firestone springs on the back of my Insight - they have enough specs available to do a proper design. The catalog can be tricky to find - it's sometimes called their industrial catalog I think. My air suspension book covers the selection of air springs where there are spring specs available.

Kelderman is probably using firestone and they did all the homework. That is bags, fittings, strut assemblies, new Rancho 9000 shocks. I really can't build the front end for that price.
The 4 link rears are where I think I could fab my own. The thing that makes it worthwhile is your control system. If I can borrow from that, I can make a speed adaptable ride, and also an off road setting.
I am looking at electric sway bar disconnects, so I can fit a beefy sway bar for on road handling, and just disconnect it when I desire more travel.

[JulianEdgar]

Originally Posted by skyking

I am looking at electric sway bar disconnects, so I can fit a beefy sway bar for on road handling, and just disconnect it when I desire more travel.

What are these? I know Porsche run them but I've not seen them in the aftermarket.

Edit:

Interesting, but I don't think I'll fit that under the Insight! What's inside the housing? A dog clutch and cam?

[Taylor95]

So what changes have you made to your steering with your adjustable air suspension?

A common problem with lifted Jeeps is death wobble, which happens when a lift is installed without adjusting the trackbar and/or control arms. How would a system like this work without causing any tire wobble?