Air Ride Height

[AZDrock]

So I am working on putting together an air ride suspension setup for my 42' ford truck rod that I am working on. I am wondering if anyone truly "lays frame" or with air ride will actually allow the system to fully lie on the frame when its deflated.

My worry is that if something happens to one of the front bags (i.e. it leaks, blows out, etc) that the front will drop and the frame could dig into the ground causing a terrible accident. Is this really an issue? Should I put in some sort of limit stop where the system can only drop it to an inch or so above the ground?

I have a frame design that is more or less just rectangular tubing laid on top of each other in a z fashion. So if the frame were to drop, the tubing under the cab could grab into the ground if dropped at speed.

 

[Old Iron]

Welcome to the site
I set mine up to be 1" off the ground when there is no air in the bags. That way you can at least get home or to a shop.

 

[soltz]

I didn't plan to drop frame but the front cross member is so low on this thing it does hit the ground in the front but not the rear. I blow a bag and learned it will stay up with just one bag and get me home. I would make sure to use four relays.
This is a 71 GMC sprint and the front cross member is nice and round and slides right the road and it's a good theft deterrent also. [cl
That's an interesting set you have. if you end up with it hitting the ground think about a skid plate [S

Good luck with it.

Nice looking project you have going on there. [cl

 

[Old Iron]

Are you going to put a gusset between the two tubes so it doesn't break.

 

[sneakysnake]

I left about an inch, but if your not on level ground it will hit.
Are you considering a panhard bar? seems like a lot to ask of those rods on the side to side play.
Welcome to the site from Okla.

 

[Sam_Fear]

Mine lays frame starting at the rails under the body. I used a 85 Cutlass A-arm suspension. As with yours, unless you loose a front and rear bag on the same side at the same time or a tire and bag on one corner at the same you're frame probably won't hit.

You might want to discuss your front end geometry with someone that knows that stuff inside and out. Seems to me those short arms are going to cause you serious steering issues. When the axle tilts (one wheel higher than the other) the short arms will make those joints bind. As your axle moves up and down it will change your caster fast. Both could cause very sudden and dangerous steering issues.

Just the fact that you only have one set of arms going to the axle means big problems. You seriously need to stop work and get help with that front end geometry. I think what you are trying to do can be done, just do it right.

 

[AZDrock]

This is only the beginning stages of the front suspension. I still haven't added a panhard bar, bump stops, and shocks to it along with a very large gusset between the two bars as you mention.

The more I have been thinking about this the more I want to just put in a limit stop to leave at least an inch or so before the frame touches when the bag is all the way down.

Yeah I had a couple guys look at the steering geometry back and forth and yes the caster is going to change dramatically as the axle travels, causing some fun issues with the steering. My goal was to do something really different with the front suspension even if it means its not going to be the easiest thing to drive. I have a couple other rides with nice suspension design for the track already that fulfill that optimal suspension need