Air bag suspension

[Desertdude]

Scott had mentioned these down in Baja and I thought it was a great topic to discuss - I have read many other threads on other sites and there seems to be pros and cons


Firestone industrial

suspension connection


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[Scott Brady]

Very cool Pasquale, this will be a good place to collect thoughts and ideas. I do plan on taking the rear suspension apart on the Tacoma while I have the 4Runner. I have a new set of custom 11 leaf Deavers being built, which will include their new Baja bushings, which is essentially a spherical joint replacement for rubber bushings, allowing the axle to flex without putting rotational stress on the leaves. I also plan on including a set of Downey shackles too. For shocks, I will be upgrading to the new Donahoe remotes with 2" body.

The goal with my airbag set-up is three fold:

1. Allow variable load control (i.e. soft when empty and maintain control and ride height while loaded)
2. Allow variable height: With the low hanging fuel tank, I want to be able to lift the rear up to 5" over static ride height.
3. Camp leveling: I want to be able to level the truck when I get into camp front to back and side to side.

My greatest concern is air leaks, so I am looking for an ultra reliable set-up. Have not found it yet

I will start the planning process in earnest when I get back from Seattle.

 

[Suty]

Very cool Pasquale, this will be a good place to collect thoughts and ideas. I do plan on taking the rear suspension apart on the Tacoma while I have the 4Runner. I have a new set of custom 11 leaf Deavers being built, which will include their new Baja bushings, which is essentially a spherical joint replacement for rubber bushings, allowing the axle to flex without putting rotational stress on the leaves. I also plan on including a set of Downey shackles too. For shocks, I will be upgrading to the new Donahoe remotes with 2" body.

The goal with my airbag set-up is three fold:

1. Allow variable load control (i.e. soft when empty and maintain control and ride height while loaded)
2. Allow variable height: With the low hanging fuel tank, I want to be able to lift the rear up to 5" over static ride height.
3. Camp leveling: I want to be able to level the truck when I get into camp front to back and side to side.

My greatest concern is air leaks, so I am looking for an ultra reliable set-up. Have not found it yet

I will start the planning process in earnest when I get back from Seattle.

Scott, I saw you are planning a set of Downey Shackles. Is that the 1.5" Lift ones? The reason I ask is that I know the Deavers have lift built into them,are you looking for more height? If so won't the back end be much higher than your front ? Just wondering about your plans or wil the weight in the back level you out with this setup? Again Sorry for all the questions, just trying to keep up with you. Now, it's seems your headed another direction, damn I'll never catch up. Tu Compadres, Suty

 

[Desertdude]

I do agree the eleven leaf pack Deaver made for my Tacoma is still standing tall - and will raise a bit when the aux tanks are all empty

Airbags do appear to have a few obstacles - and potential breakdown out on the trail -

a wild airbag setup

over the hill

another vendor for info

air ride vendor

a worthy cut and paste quote from Peter Straub speaking of adding airbags on an 80 series LC in addition to the coils - and using it for lifting above trail obstacles.

I would not think that air bags 'just to get over big rocks' is a good idea. Bags cannot really run 'empty', then inflate them when you need them. When they run empty, they get deformed as they move around, and this can cause premature wear. Just go 100% bags, or stick with coils and slide over the rocks you can't fit over like everyone else.

Bags definitely work different than coils. Having them adjustable is nice, but relying on them to keep the truck level is a huge problem. A serious anti-sway bar is definitely needed, something my rig doesn't have and suffers for as a result.

One of the nicest setups I've ever seen is on a custom buggy built by a guy here in Calgary. He put air regulators on each air bag, and used beefy anti-sway bars to keep it level. With the air regulators working, they keep even amounts of air pressure in each air bag, which results in even ground pressure under each wheel right up to the point where the limit straps come tight. Forced articulation! Works awesome. He can then adjust height by adjusting the regulators.

I used a rolling lobe style airbag, which tend to provide the most travel. Mine have 14" of travel. If I were to do it again, I would go with a bellows style bag mounted part-way up the lower link. Then you can use a bag with a shorter travel, but still get lots of wheel travel. But that might be more work than just swapping out the coils on your truck.

Peter Straub

 

[Ron B]

My mechanic has replaced the springs on his humvee with airbags. So far, it seems to be working well. The bags really smooth out those pesky wash-board roads, as well as the obvious adjustability of the truck's height. He uses the double bellows type. I was worried about how strong they were -- but they are as thick as a tire side wall, rated for way more weight than his truck, and easy to replace in the field. I guess the flip side is having one more system to let you down far-far away from help.

I've been looking at suspension lifts (nothing bling, but 2 or 3 inches would really help my truck's bad break-over angle) but they all seem to really rough up the ride and I'm trying to keep the center of gravity low. I'm waiting on further testing before I dive in head first, but so far it looks pretty cool.

any/all thoughts appreciated

Ron B

 

[Scott Brady]

I am intending to lift the truck a little more. Probably 1" in the rear and .5" in the front. With a full load, I am 3/4" in the rear over stock and 1" over stock in the front. I want a little more compression travel and a few inches more clearance at the aux. fuel tank.

The goal for the airbags is to allow load control more than anything, so even if the bags fail completely, I will be able to rely on the springs. It will just limit the amount of extra fuel and water I can carry, creating the need for more frequent resupply.

 

[erin]

I have been thinking of this also due to the 8 leaf packs I have now. My question is can you run bags just for load support that allow the leaves to articulate as always? Or do you have to take the air bag travel into the whole equation?

 

[goodtimes]

I have been kicking the idea around for the Dodge as well. The problem is that I don't want to go with just bags....I want them for load control and camp leveling. I do not want to have to depend on them to get me home. I really want to lose the leaf springs in the back, and the plan is to build a simple (ha!) mid length 4-link (plus panhard) suspension for the back.

In the article quoted above, Peter Straub suggests moving a bellows type bag (which allows less articulation) farther up the lower suspension link. This is bad for what we do, IMO. this puts the weight of the truck onto that lower link, and splits the weight up between the 4 link ends. If you keep the spring, airbag, etc. located at the axle, the weight is moved to the spring mount and axle tube, freeing up the link to do it's job....control the placement of the axle under the vehicle. You will see some race vehicles with their coil over shocks mounted on the lower arm, but look at those arms. They are HUGE, and have HUGE ends on them. Then look at the application...they are intended to soak up the washboard roads and impacts from jumping the vehicle for a maximum of 1000 miles. Then they get torn apart and rebuilt. Personally, I don't plan on having to rebuild my suspension every month.

As my thought process moves away from air bags, I come to the next obvious option....air shocks. Springs still support the vehicle, so if I lose air, I can still drive. If I have a spring that starts sagging to a point where it is problematic, extra load from pulling a trailer, etc., need to level the truck out at camp, I can do so.

Basically, using air bags is best when used as a suspension system in and of itself. Air shocks on the other hand, can be added as an accessory to a existing system. The wear aspect of running bags w/o pressure is what prevents them from being a good choice as a add-on component....plus they take up a huge amount of room......

I have a few more thoughts on the matter, but I need to go find some

 

[Scott Brady]

I am looking into the load lift style bag, which is designed to carry a load and produce extended travel. Very similar to the P38 Range Rover style airbag suspension.

 

[Desertdude]

a UK company specializing in airbag technology

 

[goodtimes]

I am looking into the load lift style bag, which is designed to carry a load and produce extended travel. Very similar to the P38 Range Rover style airbag suspension.

Scott, unless you are thinking WAY outside of the box in regards to your suspension (read: very intricate and one off.....and therefor not proven to be reliable), air bags will not extend your wheel travel. Your shocks and bumpstops will always limit wheel travel on the up (compression) side, and your shocks, limiting straps, or springs will always limit the down travel.......

Or are you referring to using a air bag as a "user controlled" overload spring...allowing you to trim your ride height as conditions warrent?

 

[Mike S]

I have a little experience with the air suspension gear. Not because I installed it aftermarket, but I specificed air suspension when I bought my Ford Expedition. This suspension is computer controlled, and replaces the shocks - so there are no shocks - just the air stuff. It has auto-sensing and leveling, and makes both highway and off-highway driving more pleasant.

I was at Murak's the other day, and saw some new air system that is self sensing and self leveling. I met the rep, but do not have the name of the product. I'll ask Gary to send a url along, and post it here.

Mike S

 

[Brian McVickers]

The rear suspension in my Discovery II is air bag suspension. It is auto leveling and adjusts by itself as the load changes. So if I put a case of beer in the back they pump up to adjust and keep the vehicle level. When I take that case of beer out you can hear them deflate a bit to allow for the change in weight. I can not control them manually but they seem to do their thing even when the engine is off. Actually I can control them a bit, the press of a button will inflate them to raise the back of the vehicle 1.5" so my 3" of lift will becomes to 4.5 inches on demand as long as I am going less than 15 mph, this is great for increasing your departure angle when you need it! Above 15mph it automatically goes back to the default setting. Supposedly you can re-program the computer to have the bags inflate for more than a 1.5" lift but I just stuck with the standard settings. This system is the air bags alone, I think it would be great to somehow combine them with a spring.