Another good reason to run Airbags

[ntsqd]

I'm accepting that it doesn't work, but the table analogy has stiff legs where a vehicle has springs in it's "legs", so it doesn't well describe the situation.

I think the reason it doesn't work is lack of force. Assuming (seems to be popular right now...) a 4" ID air spring at 30 psi there is a maximum lifting force of 377 pounds. I can see that not being enough to make much difference. If you ran that up to 100 psi then you'd have 1257 pounds of lifting force. That would probably do something.....

EDIT: Reading GT's post after starting this and then going to lunch I'm struck by one thing. The point of load bearing is where the spring(s) are anchored at the frame and on the control linkage, not where the linkage is anchored. If all the weight went to the linkage mount locations then there would be no weight to compress the springs. A Free Body Diagram of, say, a Taco's lower front control arm, is really quite interesting. Depending on exactly what the situation is the arm could be pushing up or pulling down on the frame at it's mounts.

 

[goodtimes]

EDIT: Reading GT's post after starting this and then going to lunch I'm struck by one thing. The point of load bearing is where the spring(s) are anchored at the frame and on the control linkage, not where the linkage is anchored. If all the weight went to the linkage mount locations then there would be no weight to compress the springs. A Free Body Diagram of, say, a Taco's lower front control arm, is really quite interesting. Depending on exactly what the situation is the arm could be pushing up or pulling down on the frame at it's mounts.

Actually, yes, depending on the suspension design. If you are using a coil, or coil/over design where the top of the spring is attached to the frame, you are correct, that is where the load is at. If you are using a torsion bar suspension, then the load is at the pivot point of the arm. I should have clarified that (what my mind is seeing and what my fingers type don't always match, so thanks for pointing that out).

With a little further thought, this was probably useless info anyway...because what really matters is the distance from centerline that the load is supported. Regardless of the load being at the arm pivot point or at the spring mounting point...the key piece of info is how far away that point is. The farther out the airbag is mounted, the more effect it will have when trying to level a vehicle off on uneven terrain (because it picks up less weight from the opposing side).

 

[kcowyo]

Did that clear things up KC? Or did I make it worse. eepwall:

Clear as mud.

Physics and geometry aside, all I can say is after several attempts, that trying to level the truck from side to side with the bags is a PITA. I believe it is much easier to level up, by parking on rocks, than it is to level down with the bag pressure.

I assume you all know I appreciate the input - :beer:

 

[goodtimes]

Clear as mud.

Physics and geometry aside, all I can say is after several attempts, that trying to level the truck from side to side with the bags is a PITA.

Yes. But if you have a few :beer: before attempting it, it just might be amusing to the rest of us.

:wavey:

 

[ntsqd]

Yes. But if you have a few :beer: before attempting it, it just might be amusing to the rest of us.

:wavey:

I dunno, sounds inconclusive. Assuming it's not too much trouble I think an experiment is called for!

 

[Ron B]

Now, if you are using a air suspension in the truest sense of the term, then you no longer have springs...just the air bags. In this case, you are sitting on your bump stops until you add air to the bags. You increase pressure to acheive ride height. Once at that height, you can use pressure to raise (within the limits of the suspension), or lower (down as far as the bumpstops allow) a vehicle. Since you control both up and down, you have more room to adjust for uneven terrain. You are still limited by the mechanical components of the suspension (link length, bump stops, geometry, mechanical intereference, etc).

In typical applications (ignoring rock buggies, custom suspensions, etc), your ability to level off a parking spot with the use of air bags are pretty limited. You can get a couple inches, but that is about it.

you are right, this is what I did -- staying within the design perameters of the suspension (setting the limit straps) I can safely get the belly of the truck about 4 to 5 inches over stock and about the same lower than stock (the later's comedic value is worth the price of admission). But being ifs/irs to get 4 inches the bag only has to "move" about 2 inches. I don't drive the truck at full inflation, but it sure is nice when wheeling. The bags are so strong, I'm waiting for the limit straps/mounts to get yanked out.

rb