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Air/leaf hybrid springs??

DanMan2k06

NAXJA Forum User
Location
Damascus, MD
I've been browsing around the webz recently looking at air helper springs, and an idea came across my mind. What if you used the air spring to share the load under normal driving conditions, rather than just "overload" situations. Here's my thought:

A lot of poor guys in the mini-truck world run mono-leaf setups. It saves them from building ladder bars and steps back from an expensive, complex suspension, to a simple bolt-in (and weak) suspension. They remove all the leafs except the main, and sandwich the bags in between the springs and the frame. This over-works the leafs, and eventually they crack and fail. This lead to using two leaves, for added durability. Most say it works ok, but is a stiff ride with lots of axle wrap.

Enter the jeep world- Cherokees weigh much more than a 2wd stock cab short bed s10. I've tried lots of leaf setups, and no matter what it's a compromise. Want to tow? Too stiff ride for a DD. Want a road friendly DD? Forget about towing or hauling. So my here is my idea. I have a 7-leaf IRO pack. It rides great with 400lbs of stuff in the back, but unloaded its like every other stiff leaf pack I've used. What if I removed (pick any) 3 leaves, and installed the helper springs. When the jeep is unloaded, minimal pressure would be needed for correct height and ride. When hauling, the pressure could be pumped up and all would be well. Air offers an extremely progressive spring rate, so I think it would be very adjustable.

I understand articulation would be limited, but I don't care. My jeep has been retired to an overly-capable occasional DD, camping/beach/snow ADV rig. I've tried so many rear setups and just can't find what I'm looking for. If push comes to shove it'll get linked and coiled. Is my idea feasible? Does anyone have any experience with air springs? Am I totally insane?
 
Here's one guy's experience with airbags.
He seems to like the mod.
I think it's probably what you are looking for. Get yourself a DD spring rate / shackle setup & add bags for when you need them. If you rig things correctly you can have OBA in the bargain.
 
You could just man up and buy some quality leafs. Buy some Deavers, Nationals or Alcans and they work good everywhere.

cheap shit is still shit.
 
I have BDS leafs in the rear and when towing my 3400 pound camper with a 400 pound tongue weight I was getting a ton of sag (I measured around 2.5" of drop when fully loaded for travel). It made me concerned about vehicle handling and over-stressing the leaf pack, so I put in the same air bags. I never liked them and hated how much I was constantly thinking about whether I was near the travel limit of the bags. They're coming out soon since I bought a real truck for that kind of towing duty.
 
You can try an overload spring. Some leaf packs such as from OME come with them installed.

OME CS033RA's have a design load rating of just over 1,000 lbs, using 5 leafs on the primary with 1 overload spring on the secondary. Overload springs usually have zero or negative camber to compensate for heavier loads.

As a comparison, MJ's rear springs, a different size (won't fit an XJ). The load rating, if I remember correctly, is somewhere in the neighborhood of ~1500 lbs.

Air bags I don't know, never have used them. Older Cherokee's use to have an optional OEM air suspension system with a built in compressor.

There are also rear springs specifically designed for towing.
 
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I don't remember much about them but I have seen airbags whose lower mount was a cup, so off-road the bag didn't limit droop but neither could it come out of the cup.
I think picking a bag with just a shade more travel than your shock and bump stopping like you want to keep both components on your rig makes best sense.
I've never driven high end springs but I can't see how in Physics they are going to drive as nicely while towing, moderately loaded & DDing
 
Some S-10 packs include an overload spring. What some people do is use the Jeep's main spring and cut the eyes off the S-10 pack then mate them together.

If you want to go with air bags would be another option, if not going off-road or staying mostly on logging or forest roads. If installing air bags I would think articulation would suffer and cause other problems.

Two stage or multistage springs are more common. Used in trucks and other vehicle that require both a good ride (both on / off road) and hauling capabilities.
 
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Cal, I'd have no problem dropping a grand on some leafs if I knew they were what I was looking for. But, like yossarian said something about the physics jus doesn't sit right. I wish there more built rigs out here so I might actually have a chance at riding on some deavers. I'm going to do some more heavy researching on them, and perhaps contact the company about my needs.

I'm not interested at all in overload springs or bastard packs. With an overload spring, you are able to haul the load, but at the sacrifice of height. It's simple, without sag the overload spring doesn't work. You'll need significant sag for it to actually do it's job. This comes at the sacrifice of ride height, ride quality, and ride handling. Bastard packs, well, they're just an endless time consuming guessing game that usually ride like shit.

I've owned stock replacements, pro comps, bastardized s10 packs, OME hd with overload, and now the 7 leaf 3.5" IRO's without an overload. Still searching for this mystical unicorn, and sadly I think it lies in the form of a progressive rate coil...

Th airbag idea was just that- an idea. I was hoping others had messed around with more unconventional solutions first. For ~$250 though, I'll volunteer to be the guinea pig.

The other thing I've been working on lately is the role of the shackle. Length and angle play a significant role as I've come to understand. It's much more than just using longer shackles for lift and setting them at a 45 degree angle with some relocators. The spring arc and shackle arc have to mesh as best as possible, while maintaining ride height and articulation. More to come on all that mess later.
 
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I don't remember much about them but I have seen airbags whose lower mount was a cup, so off-road the bag didn't limit droop but neither could it come out of the cup.
I think picking a bag with just a shade more travel than your shock and bump stopping like you want to keep both components on your rig makes best sense.
I've never driven high end springs but I can't see how in Physics they are going to drive as nicely while towing, moderately loaded & DDing

why don't you talk to someone who manufactures quality leafs.

give ben at national or the guys at deaver a call.
 
Cal, sorry I never got around to that call. I emailed Deaver just now with my list of "wants" in a spring.

With it being winter and all, I decided to throw some sandbags in the back to help with traction. 420lbs of sandbags. The rear only sagged about an inch, and the ride was improved, but not immensely so. These springs are just too damn stiff. I need something that will actually allow the shocks to do their job. We'll see what Deaver has to say.
 
Yeah it sounds like your leafs are not only too thick (per leaf) but also painted with the wrong kind of paint, so they don't move on each other freely.
 
Airbags alone are like $30-$50 each on ebay. I haven't priced line or fittings, but you ought to be able to get everything you need for less than the $240 kit. Fabbing your own mounts should be pretty easy too.

I'm thinking that I will probably add a set of airbags as helpers before I buy another set of leaves. The leaves on my '00 are shot from being overloaded. I've hauled home two 500 pound engine drive welders, a 350-400 pound generator, and quite a few other overloads on a hitch carrier. Saturday I brought home a 10k ramsey PTO winch and an NP202(predecessor of the NP205) off an old international 1 ton. That was roughly 400 pounds. :gee: I really need to get my old half ton chevy going again.
 
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