Air Shocks Without Springs Question

[psychomike]

Hey Guys -

I am laying out the basic pieces to begin my build. It will be a 38 Chev truck - Chopped/channeled/Zframe. I will be building the frame and for the rear I plan on using a simple two point link (as opposed to four point) with a panhard rod. The bed will be shortened and narrowed and the only weight in back will be a fuel tank and battery.
Since I dont know what the actual weight will be and cant weight jack it until I'm done I was planning on putting in solid struts in place of coil-overs until I get it done, then determine the spring rate, and replace the struts with the coil-overs.
Then I was thinking I would use an old pair of air shocks I have so I can get the ride height dialed in while building it. My question is: can I just use air shocks without springs as a final means of suspending the vehicle? there will be very little travel in the back and very little weight so a nice set of coil-overs seems kind of a waste. Has anyone done this? Why should I NOT do this? Why is this different than Air Bags?

- Mike

 

[Hopsing]

The airbags out now are designed to support the weight and load needed to suspend a vehicle. Airshocks werent. Doesnt mean that they wouldnt, they are designed as an assist.

People use them on the front of VW bugs all the time, but those front ends are way light.

Now, back in the day of mini trucks before airbags. Alot of trucks were running around with airshocks as a complete air adustable suspension. If you are going to do it, RANCHO Suspension brand is what I would recommend. Thats what everyone used back then with the best luck. The cheaper ones never seemed to last or work as well. They have them in different sizes and mounting styles. Check out your local off road shop for a catalog.

 

[Cyanide Jello]

If you're trying to suspend the whole back end w/ an air shock, the shock itself is more than likely to fail... You kinda confused me there, you said you're gonna use a strut and then go over to a coil over... To me thats the same thing... Now if you're talkin bout an independant coil and shock thats different...

Air bags are completely adjustable and are made to handle a load and suspend a vehicle entirely... If you're looking for adjustability at the flip of a switch thats your best bet other than hydros... But you're talkin bout some bux, and you'll need that 4 link for best performance...

Or like he was saying, if you wanna go old skool mini you could always hack your coils out or weaken them a great deal and run air shocks and keep the valves open and run air line to them hooked up to a manual paddle valve inside the cab linked up w/ a small compressor and air tank...

You could also just run adjustable coilovers... Advance or Autozone sells them for s10s, they are eye/stud configuration...

 

[psychomike]

My apologies Cyanide Jello - when referring to a strut what I meant was a solid piece of steel with an eye on either end. It supports the chassis at a given height - we used to use them when building race chassis to maintain the ride height we wanted during fabrication (or when we stole the springs for use in another car for the weekend). I was just looking for a cheap alternative to a nice pair of coil-overs and happen to have an old pair of air shocks.

 

[donsrods]

Please don't use air shocks as your only support, they were never intended to act in this manner and will break at the worst possible time. During the '70's, which was the darkest period for car building in my opinion, people were doing crazy stuff like this, and some people used air shocks as you have suggested. Those cars are no longer around, and I wonder how many of the drivers are also gone too as a result of using them.

Use tried and true parts and you will be safer and so will everyone else on the road.

Don

 

[psychomike]

Good enough for me - Thanks Guys !!!

 

[Unkl Ian]

Why should I NOT do this? Why is this different than Air Bags?

- Mike

Air bags are typically 5" or 6" in diameter.
Air shocks are around 2" in diameter.

A 5" dia bag is 19.625 square inches,
a 2" air shock is only 3.14 square inches.

Based on these areas,to support the same load,
2" air shocks need 6x the pressure of a 5" bag.

So the pressure in an air shock would have to be
unrealistically high to support the same weight.
Your compressor doesn't want to work that hard,
and the air shocks won't live at those pressures.

 

[Rev Tex Devlle]

get ya self a set of harley coil over shocks and add the air shocks,, works good,, for the amount of weight you will be useing,, i have harley sportster shock and at 235 pounds i can only push the rear end down about 1 in',,

 

[wsdad]

I think they will work. Here's why...

...the pressure in an air shock would have to be
unrealistically high...
...the air shocks won't live at those pressures.

From the horses' mouth:

http://www.monroe.com/products/maxa...ader&currSubItem=&rolloverObj=[object+Object]

"The Max-Air® shock absorber is ideal for vehicles that haul heavy loads or tow trailers. Designed to maintain level vehicle height, they can be inflated or deflated as needed...from 20 psi to 150 psi with the vehicle loaded."

Sounds like they're made to handle the extra pressure - up to 150 psi.

If you're trying to suspend the whole back end w/ an air shock, the shock itself is more than likely to fail...

...Air bags are ...made to handle a load and suspend a vehicle entirely...

"A pair of Max-Air shock absorbers can maintain ride height when up to 1,200 lbs of additional weight is loaded."

That's 1,200 lbs on the rear half of a car or truck. Does your T-bucket weigh less than 1,200 lbs in the rear? If so, they should work as designed. If you used them at both ends, they could withstand a total vehicle weight of 2,400 lbs., assuming a 50/50 weight ratio. (They don't recommend using them on both ends, but I don't think it's because of safety issues. It's probably because the rear is where most vehicles carry their extra weight in a typical application. Normally, you wouldn't want to raise the front of the typical vehicle so there's no need to put them there.)

They are made to DAMPEN a regular vehicle's entire weight plus the vehicle's rated payload capability, plus SUPPORT an extra 1200 lbs (think full size car or pickup truck fully loaded). They have to be strong enough to dampen all that weight while hitting a bump hard and at speed. They have to be made pretty rugged. They have a "1/2 inch Piston Rod: Hardened and precision ground rod for consistent performance and long service life." It would be interesting to see how thick a McPherson strut rod is in comparison. I don't have any vehicles that use struts or I'd go run out and measure one.

Most T-buckets aren't more than 2,400 lbs. If you put them on a T-bucket, it sounds like they would be well within their design capabilities to me, even without any other springs. It's just my untested opinion but it's based on their published numbers and the weight of a typical T-bucket.

I think the ride will wind up being too harsh if you pumped them all the way up to their max, anyway. You should have plenty of strength and safety to spare.

I'd at least try them since you already have them. It would be very easy to install coil overs in their place if it doesn't work out for some reason. They should work very well and be very safe, IMHO.

Please try it out and report back. I'm thinking about doing the same thing.

 

[Ed ke6bnl]

another part of this issue and I found it on my 72 el camino was the shock mounts are not designed to handle this load over any lenth of time.!! The guy I got the truck from used them to haul dirt bikes and ripped out the supports in the frame. Ed