Why use air bags? Why not Monroe air shock?

A friend and I were bench racing the other day. He asked me, "Why not use those load-helper air shocks in place of air bags?" It seemed like a good idea to me. We couldn't think of a down side.

Here's a link to Monroe's website. Are there other manufacturers?

http://www.monroe.com/products/mp_detail.asp?cat=0&detail=Max%20Air

Here's some advantages we thought of:

1. Less cost. You could use the existing suspension mounts instead of buying new A-arms.
2. Easier construction. Why go to all the trouble and re-engineering when you could simply bolt in air shocks? Shock absorbers are used on some bag suspensions anyway.
3. They take up less room.
4. They can handle more heat.
5. They look more traditional.
6. You can paint them.

Here's the only disadvantages we could come up with:
1. The stock suspension may not drop as low as a totally re-engineered suspension with bags. (You could re-engineer the suspension using air shocks.)
2. You would have to use softer springs. (Take leaves out; heat or replace coils; adjust torsion bars; not a big deal.)
3. They are made for trucks. Perhaps the valving/rebound characteristics may be off for a light car?
4. They use more air pressure.

We couldn't think of a real down side that can't be overcome. Are we missing something? Why isn't this wide-spread? We've got to be missing something obvious.

I want to try this on my car. Somebody tell me why not before I go to all the trouble.

 

Becuase shocks are not designed to suspend a car. It would be dangerous. Load leveling air shocks are designed to be a helper to your existing suspension.

 

sounds to me like you're reinventing the wheel a bit.

 

I don't understand. The air bags are basically the same thing, putting the suspension loads in the same place.

 

most air bags are rated at 2000 lbs each. If you heated the springs to go down all teh way to the ground to get the desired stance, when you lifted the car up with the air shocks you would be rolling on a small shck not designed to support the weight of your car. It could easily break. As far as leaf springs go you could runa 1 or two leafs but again the weight of the car would be on the shock and not the spring. Bags are designed for supporting weight. Shocks are designed to absorb energy. Load leveling shocks are designed to help the existing suspension do its job.

 

this man speaks the truth

 

people used to do this alot in the past, a few issues that could be argued are designing a suspension system completely around an item that has a limited amount of travel, using a helper part such as a spring in the front could cause darting because of unloaded torsions or collapsed coils from heat. If you put the entire wait of the front of your 4000lb car on a set of bags that combined can handle atleast 5000lbs with an appropriate shock the handling characteristics are more predictable, but to have the entire weight of your frame, body, you, motor all crashing down at once on a shock that is just meant to assist it is probably going to blow out quickly and it is real bad if it occurs while driving. Dont get me wrong, i have done it when i was younger when they were not other options besides hydros but there are alot of things we have all walked away from we had no business doing. Like said above it is like reinventing the wheel, atleast helper bags are set up to not bottom out before the suspension, to set up air shocks this way would be alot of work just for 3inches of travel. Sorry long winded, just my 2 cents.

 

My thought is if it is worth doing, its worth doing correctly.

I restore Mopar Muscle cars, along with building Rods and Jeeps, I cant tell you how many rear shock crossmembers I've hade to Replace/Repair/Fabricate on late 60's cars because they had air shocks in the back. They DESTROY the shock mounts when used to lift the car for bigger tires etc..

 

Damn I type slow, or you guys are quick!!

 

If you had ever owned a car with air shocks on it and aired them up to raise your car a few inches, you would not needed to ask why not.

 

Air bags replace the springs. All air bag suspensions should have shocks, if they don't something is wrong. Just a couple of things that seem out place.

 

Another reason beyond those pointed out is that there is very little air volume in an air shock compared to an air bag, plus the air chamber in an air shock is shaped differently. It's a cylindrical bag with part of the shock passing through the center of it, whereas an air bag doesn't have anything in the center of it. What this means is that an air shock has a lot sharper "stiffness" curve than an air bag. I don't know exactly how to explain it, but if you compress an air shock halfway, the pressure inside the air chamber may increase 200%, whereas in an air bag it may only double. And trust me, if you ever rode in a car that had air shocks pumped up a little ways you'd definitely feel the stiffness of the ride. They suck for anything except what they were designed to do, which is to assist a proper suspension when the vehicle is loaded heavily.

You could probably build a suspension that could use air shocks as a major load-carrying component, but you wouldn't be happy with it.

 

The answer is in the part description - air shocks. They are not springs.

 

Your age is showing here.
Or maybe it’s my age that’s about to show. Hehe.
<OWe used to do exactly what you are talking about back in the 70s when I was in high school.
<OThe old Gabriel Hi Jackers (remember the rabbit sticker) a little air and you had economy funny car rake!<O<O
The ride whoever was harsh no matter how little psi you ran.
<O<OIt is cheap but I think the rough ride and lack of travel will convince you to go full air ride.<O

 

Good point murfman had on the shock mounts too. They are definitetly not designed to suppor the weight of the car. Its just dangerous all the way around.

 

AHH the jackrabbit shocks. a buddy in high school had those on his GRABBER MAVERICK. Used to jack er up in the back to gocruisin. Rode like crap.

 

Air shocks tend to deaden the suspension. Like in the old days with the jacked up rears for tire clearance, I can't tell you how many Chevelles, etc that I saw with ripped out shock mounts, upper and lower.

If you have a family car that you want to load camping gear in or tow a boat once in a while, air shocks are a pretty good thing. For hot rodding, bag it!

Bob

 

I wouldn't use air shocks instead of airbags... like everyone else is saying, do it right. and air bags without shocks don't ride very good either. take all four shocks out of your 5000 lb cruiser and go ride some back roads. thats what air bags feel like with no shocks.
VWs do use just air shocks on the front of bugs and stuff when they are put on air. but the wieght on the front is pretty much nothing. Other than VW's I wouldn't do it

 

We bagged my wifes Comet. It has shocks in the rear. The front has no shocks . It rides fine. She roll with it all the way up in the front. I would recommend shocks though. We just have no mounts for them in the Comet. I may make that my next project

 

My first experiments with adjustable ride height were monroe air shocks working together with rear leaf springs. I could get a couple of inches of lift for driveways.

My main problem with the shocks were they used a very small diameter air line. Also at that time air tanks and valves really weren't available to work with that small diameter line. So one asks, why is a tank needed? Often while driving I would have about 3 or 4 seconds to see a driveway or speedbump coming up. I could not air up the shocks within those 3 or 4 seconds using the standard air compressor that is designed for the shocks.

I saw an early Air Ride Technologies demo chassis with the 1/4" line (woo hoo, big line for the time), complete with a system of valves and tanks. I was convinced after seeing that chassis, the shocks were just not going to be good enough. Also, the other posters are correct in that shocks do not have the lifting capacity of air bags.

 

Wouldn't really look traditional, either. The air shocks are much bigger around than regular shocks. They would look better than bags, but would still look off.

 

on a full fendered car would the look of an air bag really cause it not to look "traditional". From the outside you can't see that there are air bags. and if you have full inner fenders you wouldn't really be able to see them from the engine compartment either right? I can understand on a fenderless rig that you wouldn't want to see an airbag on the front, but even on those you could hide one under the back somewhere. Or if you got real creative you could hide the entire suspension portion under the car and you wouldn't see anything.

Later,
Chad

 

that's what I'm talking about!

 

You can even hide them up front on an open wheel solid axle.

 

Ok here is the skinny.....

AirShocks....... airshocks are exactly (kind of) what their name implies and they actually have improved (slightly) from the hi-jackers of the 70's. they are realistically nothing more than a pneumatic cylinder. They do not exhibut a spring rate like a traditional steel spring or airspring. To be quite honest even the shock dampening factor of a MODERN airshock is barely marginal at best.

Airsprings...( bags, airbags.. or whatever you want to call them )
An Airspring is a spring... it exhibits an spring rate like a traditional spring other than the simple fact that it is adjustable by the volume of air that is displaced inside the spring. Like all springs, they HAVE to have a shock because they have no dampening properties themselves.

So lets break it down at this point, if you are looking to lower the vehicle and then bring its ride height back up you need additional spring rate to help you do that. You accomplish that by adding airsprings, not airshocks. Now there are a couple of other options you can go with but you have to remember. most rear factory OE shock mounts are not engineered to take the kind of loads it requires to lift a vehicle up so you will need to do check yours out and do some re-inforcement if needed but you can use a Shockwave... or if your pocket book is on the ritz you can even go and boneyard you some rear leveling shocks out of a new Bonneville, Park Ave, tahoe , suburban ect.... They are kind of like an OEM shockwave and actually have an airbag with a shock running through the center of it. If you do that, you better pay attention to the manufacturers installed height settings and duplicate it... how do you do that you ask... easy... go measure your retired neighbors park Ave while it is sitting in his drive way. At best you will get the measurement you need. At worst, you will get accused of being a terrorist. If you are in Ca. or the upper N.E. it might involve a slap on the wrist along with a minimal prison sentence or community service at the local non for profit PETA benefit. If you are in Texas or the Midwest.... you will morethan likely get to meet the man they call "Peter" and see his bitchin gate.

 

My 1st car was a '73 Nova w/ Monroe airshocks... if you let the air down it would ride low and it would bottom out LAMF. Over filling with air would jack it up -- and then every bump in the road felt like the end of the world. Plus horsing around with the PSI dogged the shocks out in no time.

 

Air bags are a much larger diameter.The added area increases the load capacity,
for a given pressure. Air shocks are much smaller,so they would require an absurd
amount of air pressure to support a load. Do the math.

 

I used Gabriel SkyJackers on the front of my '64 VW to fully support the weight. Even though the front of a bug weighs only a few hunded pounds, it took 200psi to get it to ride hieght. I couldn't imagine how much pressure it would take to get the front of a 50's car off the ground....lol

 

When I was in high school in the 80s, 70s Camaros with air shocks to raise the rear end to clear N-50 tires on 10" Cragar five spokes were all the rage. They were so stiff, sometimes the rear tires would bounce off the ground on a bump; if you had your foot in it, the tires would chirp apon landing. Oddly, we found it very amusing, especially if it was a buddy's car and he was passed out cold the whole time.

 

If you install them upside down it will pull the car down when air is applied. I have not tried this but heard it from a tradtional car guy...