Air ride help

[Sootscooter]

Anybody running a Kelderman air ride system on their W350 4x4? My truck has front and rear bags and I was curious what air pressure I should run them at to get the most out of the system (ride comfort) with the bed empty. Thanks- Ryan

 

[1stgen4evr]

air ride

I have some brand of air ride on my D350. The bags were on the rear end of the springs. Because this often caused a problem with the rear ujoint, and because they didn't seem to have any real benefit like I expected from experience on larger trucks, I moved the bags to a location over the axle, outboard of the frame. This has been more satisfactory than the original but still not what I want. The bags have internal stops which don't allow the axle to move full range up and down and will pound on bumps if the bags are less than about 60 psi.



I realize that is not the question you asked but wanted to make the previous comment before saying that what you will get best result from will be a pressure that will carry the weight on the bags rather than on the springs. This will require some experimentation and will of course require that it change for a given load. With fwd, your setup may not have the problem that I had but I suspect that you have similar result. Keep in mind that the bags will only be useful with a very light load and you will still have a spring ride under heavy load condition.



I have recently gotten a Firestone air bag of a different design which is like the big trucks. I plan to put these on my truck in the position of the current bags which as I said are over the axle. These will allow a longer stroke and will carry the weight on the bags over a much wider range of weight.



One result of having the bags over the axle has been that my springs which have two less leaves than standard are still arched very high and the truck sits (on the rear) just as it did when new. Regardless of load, the springs are never severly bent.



Should you be interested in how I mounted the bags, I will describe in greater detail in a PM.



James

 

[Philip]

1stgen the setup he has replaces the rear spring hangers with a custom mount for the air bags. This link shows how his is setup. It is completely different from the type of air bags your thinking about.



http://www.keldermanmfg.com/productdetails.php?id=94DDGREAR



I wish I had that setup on mine.

 

[1stgen4evr]

Thanks Philip. While I didn't remember (age related) the name of my air ride, it is the same as the one in the info you suggest. Or I should say was.



Kelderman states the following:

The Kelderman Air Ride is not to be confused with just adding an Air Bag between the axle and the frame. This type of system is merely a helper for the springs to allow additional weight carrying capacity. It does nothing for the riding qualities of the vehicle and in many situations degrades the ride. You do not get additional load carrying capacity with the Kelderman Air Ride, nor do you sacrifice capacity. The only thing you gain is ride comfort. And isn't that exactly what you're after?



------



Others may have a different opinion but mine was and is that the system didn't do a whole lot for my ride and as clearly stated, didn't increase the load capacity and in MY CASE reduced the load capacity in that I was causing failure of the rear ujoint from crowding the action of the joint by the addition of the bag system as they provided. I feel that the ujoint problem could have been rectified by adding a spacer under the center mount bearing on the drive line. But that is not the way it progressed at the time we were making changes. The comment from their litterature suggesting that putting the bag over the axle is "merely a helper" is quite true unless other changes are made.



Putting their (Firestone I think) bag between the frame and axle did indeed degrade the ride since there was such a small amount of action with their bag. The solution to improving the ride required that some leaves be removed from the spring group. This still leaves the truck with less than desirable ride qualities if the bags are run at lower pressures allowing the internal bumpers on the bags to pound the truck. This will be the case even with light loads. That is the reason I plan to redo the air bags using a different type bag which has a longer stroke. I plan to remove one more leaf from the springs or maybe get the spring group from a 1/2 ton. This will allow an easy ride and still have the ability to load as needed by using whatever pressure is required to run level. And to turn a phrase, THAT is exactly what I am after.



None of my comments should be taken as degrading toward the Kelderman product. Had I used it as designed, it would have been fine. Even loading the h*** out of my truck, the Kelderman system didn't fail. I have a second truck which I use in a much lighter capacity and it has the Kelderman system and is OK. I think their litterature suggest a pressure for best result.



None the less, nothing is so good that it can't be better. I was and am striving for better in regard to ride which is notoriously rough on our trucks.



James

 

["Mad Max"]

I was looking at doing the Kelderman thing as well, but I have a local fabrication bud that builds rock crawlers and he and I are creating a complete air suspension system from scratch. We're building a complete custom 4-link suspension, front and rear, with air bags at each corner, and I'm boxing in the entire 21' of frame on my rig, which will dramatically improve the strength of the frame, and make the suspension actually articulate. I don't know what the psi will be for the bags, but they will be big beefy suckers that because of the internal surface area won't need as much psi as a smaller bag, which should also make the ride nice and smooth yet firm - add very good shocks to that, and the rig should ride like a dream - and it'll carry any amount of reasonable weight I can throw at it by increasing the psi. The rig will have onboard air, so I can also run air tools, and the front/rear psi rates will be monitored by an internal gauge that with the flip of a switch will read either the front or rear psi. Should be sweet.

I can't offer any more specifics than that, but there it is. Pics and details to come hopefully by December.

- Sam

 

[Philip]

I didn't know you had that setup. Post some pic's.

 

["Mad Max"]

Phil - you mean me? Well, I don't have it yet, but it's coming :-laf

- S

 

[1stgen4evr]

air bags

Sam, I think you can use whatever size bags (within reason) and get similar result by adjusting pressure. I would select the size based on space constraints. On my truck, there is little space outboard of the frame and that will dictate about six inches of diameter. We had an International truck for a short time (a trade thing) and it had about ten inch bags with a factory suspension. Rode great as far as the rear is concerned. Like you I am considering a leaf sprung front axle even if I don't go fwd so I can use leaf springs and bags. My front is begining to sag and that would be a fix. PM if you have done any cutting on the cab and let me know how that is going.



James

 

["Mad Max"]

Hi James!



Actually bud I'm doing a 4-link in the front - no leafs on the truck anywhere. I think I just like to make my life as difficult as possible... or something

I'm also modifying the Dana 60 front axle to replace the factory steering sith a crossover setup - custom knuckles above the kingpin on the right side that will allow for a long arm steering link, much like a real long drag link. This will completely eliminate any chance of the 'death wobble', and will be killer strong. There will be nearly zero arch on the arm travel and that will negate any wobble. Fortunately without the leafs that also allows for virtually unlimited clearance for the bags, and we'll probably move the spring perches (used as the base mounts for the lower bag brackets) out a bit to accomodate a bigger bag, and that'll allow us less pressure in the bag andmore articulation. I'm just waiting to see how big the suspension 4-link arms end up being! Something about DOM and really freaking big come to mind... .

- Sam

 

[Sootscooter]

Thanks guys- I was actually interested in what the air pressure others were running, and how tall their front bags were. I have owned trucks with a rough ride before, but this one may take the cake. Hopefully the Kelderman's will only be on for a little while. Like Sam, I am puttin a four link plan together for the truck. If anyone has Kelderman specific info, please post or p. m. me, and thanks for the replies. Ryan

 

[TKingsbury]

I don't know if I read this or just dreamt it up, but isn't it supposed to be just enough air to make the lower part parralel with the frame when at rest?

Travis. .

 

[1stgen4evr]

Ryan, the link that Philip included is the Keldeman site. They have recomended pressures.



Travis, yes, the lower link arm is supposed to be parallel with the frame. But remember that I was loading a bit heavy and as their literature clearly states, the Keldeman system will not increase load capacity. It DOES make an empty truck ride better.



My experience with the Keldeman bags mounted over the axles convince me that the proper bag at that location will do both; improve ride quality and increase load capacity.



James

 

[TKingsbury]

James, did you remove the Kelderman parts in the rear and put the stock shackles back on when you moved the bags?

Travis. .

 

[MMiller]

I have the kelderman unit on the rear of my 93 and have had very good luck with it. Mine happens to be the style with one bag in the middle of the frame. I can't remember what style is on your truck, Ryan. Kelderman makes two styles, one with a single bag and one with a bag at the rear of each rear leaf spring.



On mine, I have no idea the pressure I run when empty. I just stick my head under the truck when inflating the air bag and I stop putting air in just before the hinge assembly hits the lower stop. I know my kelderman in conjunction with the skyjacker front springs makes the truck ride ALOT better then stock. My truck is 4X4 and came with overloads, basically the most springs available from the factory.



In all reality, just run enough air in the bag to lift the truck up. When you pump them up hard, its, not going to help, and if its too soft then the bag will bottom out and the springs will jolt you. Good luck. I have been very happy with mine, I have rear only.



Michael

 

[MMiller]

Oh yeah, Kelderman makes 4 link kits now too, probably not for first gens yet.



Michael

 

[1stgen4evr]

Travis



Yes, the stock spring hangers are back as factory installed. The springs are less a couple of leaves and I do not reccomend the keldeman bags over the axle but they have served MY needs well to a point. I plan to use a different bag with more travel. I will let you know when I get it done and how it works out.



James

 

[TKingsbury]

James. How many leaves did you remove? Do you have a problem with spring wind-up (axle wrap or wheelhop)? I was kinda thinkin maybe a guy could cut some of the leaves off behind the perch, leaving the top 3 or so leaves alone. That way the front of the spring would be stiff enough to control wind-up, and the few leaves in the rear would be there for positioning and lateral control. Then the airbag would be supporting most of the weight and controlling the ride. Just thinkin out loud.

Travis. .

 

[1stgen4evr]

Yes I have some difficulty with wrap/hop. I have been able to control that with a carefull clutch action most of the time. I understand your suggestion and don't know what to say as to controling wrap. Look at a factory air suspension like International has used on some of their medium trucks and you will see that there is no rear connection. So I think your suggestion definitely has merit. I would think that something like Sam is doing with a dual arm tubular link would be most effective. It was suggested earlier in a different thread that I should drop the center bearing on the driveshaft. I have not tried that but think it would help some. And by the way, all trucks with bags exhibt hop to some extent. Just seems to be the nature of air suspension.



The current bags will handle WHATEVER load I impose and I am fairly certain the new bags will make a difference in ride because the only negative now is that the bags must be rather pumped to keep even small bumps from impacting the frame and pounding my a**. The double section bag has an internal bumper and very limited stroke.



Bags, yes. Kelderman style bag mounted over the axle, no.



I have not seen the single bag setup that Michael mentioned. They may be better than what I have in the standard setup. And again, the truck that is fitted with the standard Keldeman rides ok empty. However, my 70 model ford one ton with helpers rode just as good. The negative with those were that on a really hard bump, everything rebounded quite hard and would throw the occupant to the ceiling. I should mention too that I don't know what an empty truck looks like. The only time I ever saw one was the first day.



James

 

[Sootscooter]

Thanks again Fellas- My system has two bags up front and two in the back. Im gonna spend some time experimenting this weekend, Ill let you know what happens.

Ryan

 

[TKingsbury]

James

The reason I say leave a few springs on the rear portion is for axle positioning. Heavy duty air suspensions have a panhard bar to locate the axle side to side. A guy probably could just cut all of the leaves off and put in a panhard bar I guess. Heavy air suspension generally does generate alot of lift (especially when empty or light), but no wrap. You mentioned samsrams 4 link deal. While 4 links are cool for offroad articulation, I don't think you would want one for a daily driver/tow rig. I've been around a fair bit of it, and it is easier to make a 4 link work bad than it is to make it work good. Your link placement must be right on the money or it will work like crap. Sorry for the thread hi-jack guys, I just like talking ideas.

Travis. .