Dual air bags

I'm not sure how you'd mount them. Sounds like you need some spring work.

?? Interesting...

I had thought they were separate already, one on each side... I know you have an option of both bags filling or each one independant..

I had two on a smaller truck, but it was one fill for both...

standing by for more info, thanks..

Your sig says Kelderman Air Ride? And you have airbag assists too?

If you are talking about the usual Airlift/Firestone kit, you might want to check the Hellwig version, if it is available for your truck. They use Continental bags that are quite a bit bigger than the others, and run at lower pressure. Mounting issues are pretty much the same though.

I think maybe you are overthinking the subject. In my opinion, if you need a second set of air bags on a 3500, you are way past due for a larger truck. Think maybe you are trying to reinvent the wheel?

Wayne

Just for grins, do the math on the bags;

5" diameter bag is 20 square inches of area that the bag carries. For each 1 pound per square inch, that provides 20 pounds of carry capacity. A bag that can be inflated to 100 psi, that's 2,000 pounds per bag. Two bags, one on each side, is 4,000 pounds for a pair of bags at max inflation. This is on top of what the stock suspension carries.
And you want two each side??

Your tires and wheels rating is going to be way over long before you max out the stock suspension with a pair of bags would put you. You need to rethink what you are doing.

I know one bag per side can handle it.
I don't need a larger truck.
My tires aren't overloaded.
The Kelderman Air Ride setup I have is the two-stage. That's the one that replaces the rear spring shackles with air bags on a hinged mount to take the harshness out of the ride, especially when empty.

Spreading the load across two bags per side will put only half the stress on each one, it's mounts, and that spot on the frame. I think I'll do it, it'll be a superior setup.

Your OP says you have a set of air bags in a context that they are there to carry load. It says you want to add two more because you carry HEAVY load.

After several replies, you come back and say you have Kelderman Air Ride.

I can tell you not a single person is going to take your first post and figure anything OTHER than air bags over the axle. Kelderman is nothing close to that. Kelderman is not designed to increase load by even a single pound. They are designed to ride on air while the truck is empty so you don't have a harsh ride.

I've never heard of 'em, had to look 'em up;
https://kelderman.com/shop/1994-2002-ram-2500-3500-2-stage-rear-air-suspension-longbox



Photo shows, the rear shackle is replaced with an air bag. No extra capacity for load, strictly for a smoother ride when empty.

I apologize if I'm not doing a good job of painting the picture here.
It's got both kinds of bags.
You're correct, the Kelderman mentioned in my sig isn't a capacity-increasing thing. Its only function is to smooth the ride mainly when empty. Makes my wife not hate the thing.
It's also got over-the-axle bags to stiffen it when it's loaded. I''m just thinking that using a tandem pair of over-the-axle bags would be easier on the frame, the bag mounts and the bolts that attach them.
Seems to me that spreading the load over twice the mounts at lower pressure can't be a bad idea.

It's not that the current setup isn't working... its partly that I'd like to spread and reduce the stresses and partly that it ain't broke so I feel the need to fix it!

The 2nd set of bags are going to place the 'same' amount of force on the truck frame as the single-pair that you have now.
The bag brackets are designed for their maximum capacity, don't be afraid to pump them up.
You might get a slightly better ride by running 2 pair of bags. The larger volume will contribute to this.

The problem with adding the second set is, nobody's done it yet and there is nothing designed for this application.

You're completely on your own designing the mounting and ensuring that it isn't going to put undue strain anywhere and make things worse than if you left well enough alone. I mean, it's not rocket science and you'll probably come out okay, but there is always that chance you miss something important.