air springs and camper hauling

[underdrive]

So right now our old 1-ton truck has some rather stiff leaf packs, handles our 3000-lbs camper great however when said camper is not in the truck the truck rides like it might as well have the rear axle bolted directly to the frame. We want to change that, and our initial idea was switching to halfton leaf packs and then running air springs on top of them, air springs would have individual controls with a crossover line with a valve - on pavement crossover valve is closed and springs are adjusted individually, offroad the valve can be opened so the bags transfer air side to side for better axle articulation. Sounds good in theory, but what about reality? We've seen on other websites some people complain that air springs even isolated side-to-side are still not very good at keeping sway at bay (especially if ping tanks are involved for added air volume), right now we have very little sway and would love to keep it that way. Truck already has the biggest factory swaybars available, I suppose we can look into what's available for the higher-GVW trucks but those would limit suspension articulation unless we fab up some rather beastly quick-disconnects at least for one side.

So the other option would be to again use the halfton soft-ride leaf packs, but on top of them have some rather serious overload packs - if we allow significant space between the overloads and their frame brackets when truck is empty, this should provide enough travel and articulation for the rear axle. Then when camper is loaded truck will have to sag down a few inches before the overloads even make contact with the frame brackets, but once they do that is where the buck will stop, there will be a minimum amount of suspension sag past that point and the overloads will also help keep sway at bay. This will also have the added benefit of a lower center of gravity with the loaded camper.

The front axle is getting air springs on top of the leafs either way, so front ride height can be adjusted as needed to match the rear. Air springs in the rear would be nice for comfort and soft ride and ability to level camper regardless of terrain, but sway is a major concern. Does anyone here use air springs as their main load supports, with the leafs pretty much only locating the axle on the frame and not doing a whole lot it load carrying? We'd love to hear what people experience with these things...

Thanks!

 

[kojackJKU]

I would try to get the leaf packs to work as intended, Just not be super stiff. Then accentuate with airbags. That's the proper way to do it. I would talk to a spring maker and tell them what you have and what you intend to do. They will set you up. I have my suburban being outfitted with airbags for towing trailers.

 

[Seabass]

Ok- I had a Ram 3500 dually- with firestone ride rights. I also had two extra springs per side. It rode awful! My solution- I simply aired the bags up enough that they carried the truck instead of the springs. It rode like a rocking horse when the truck was unloaded!! When a big load was on or behind the truck I balanced the leaf springs with the air bags- not too much air, not too much leaf spring. I hauled some 30,000 lb loads. I know- WAY to much weight! But the ole cummins liked it heavy- I just couldn't stop to well. Today I've got the exact same setup on an f-350 and I'm doing the same thing- only it's not a dually so I don't load quite so heavy. I highly recommend this. And plum the bags together- they'll be fine.

 

[underdrive]

Kojack, those are the factory main leaf packs we're running now, they are working exactly as designed. It's just the truck is built for hauling heavy and it shows, when loaded down it rides and handles great. The only modification we've done are beefed up overloads on top of the main packs so they can support the heavy camper better (which they do), but those don't come into play when truck is empty, they only touch their frame pads and start helping the mains when there is a big load in the bed or on the hitch. When the camper is in and the overloads start doing their thing the truck actually rides pretty decent, it's just that we have the leaf packs designed for lots of wright all the time, while most of the time the bed is actually empty or hauling big but light stuff. Truck usually scales in at about 7500 lbs, which is around the GVW of the respective halftons - that's why we figured go with factory springs designed for weight that matches ours good 90% of the time, then gain the extra load capacity via either overloads or air springs.

As for getting custom springs made, that's kind of out of our budget right now. We already have the halfton springs, the air bellows, and air line and valves - we can build the thing either way for little to no out-of pocket expense, which allows for more time spent out there actually enjoying what we're building it for :sombrero: Besides we've been in custom spring hell before, kinda hesitant to jump in that water again...

Seabass, our idea is for the leaf packs to carry most of the truck when it's empty, just a little air in the bellows to keep them from collapsing. Then when camper goes in we just up the pressure, so basically the empty truck still rides on steel and the bellows are what supports just the extra load. We've seen it done, it works great, but it was on a truck that mostly pulled big trailers - his center of gravity does not go much higher than factory, whereas a camper (or any other tall load well secured into the bed) makes things tend to be quite a bit more tipsy. That's really our main concern, we know the bellows can hold the load and provide great ride, but our fear is they may be a bit too "soft" and not necessarily induce but at least not fight well against body roll when sudden course corrections are needed. If it was just a trailer we were pulling, or hauling stuff like gravel and stone and what have you, then that'd be a no-brainer, air ride and go!

 

[Surlybeast]

What about softening your tires in the back when unloaded? I used to back down to 45psi in my f350 empty. I wouldn't mess with the springs. It sounds like your truck works perfectly loaded up. 1 tons ride like crap empty. No way around it.

-jorge


01 Reg Cab Tacoma

 

[underdrive]

Dually truck, so doesn't really care what the air pressure is, but running 60-65psi and tires are about to touch so can't go any lower than that.

And I agree it works great when loaded up, problem is most of the time it's not loaded like at all. That guy I mentioned with the air-sprung trailer hauler, that thing rides like a 70's Cadillac even empty, we want that. But again, he tows heavy down low, we carry heavy up high, which is the proverbial stick in our wheel.

Another option was actually just brought to our attention - many electric/telephone/cable companies boom trucks built on light medium-duty chassis (think F450) have a massive swaybar running on top of the frame and under the bed, it's basically a very very big torsion bar with pivots bolted to the frame and arms connecting to the spring packs at the top plates for the U-bolts. Something like that could be the solution to any possible body roll issues the air bellows may present when camper is loaded, and being attached to the frame (as opposed to the axle which is how our factory swaybars are) it can neatly stow up and out of the way when it's not needed (after disconnecting the end links of course, but that's no big deal). I can foresee a wrecking yards raid in our near future... LOL

 

[redthies]

I know it doesn't matter a whole bunch on the surface, but you should fill in the gaps by telling us (in your signature found in user control panel) what year, make and model of truck you have, as well as any modifications you have done. That will help us help you.

I had a similar scenario going with my '98 Dodge dually. I just learned to live with the ride. The biggest problem I see with the airbag option is what do you do when you lose a bag? I have had one rub on the spring pack after the mount shifted, which caused a hole and need for a new bag. I limped home (with my 3300 lb camper on), but with only 1/2 ton springs you'd be dead in the water. My new 3500 is a srw, so I can lower tire pressure to help with ride, although I haven't played with that yet.

 

[underdrive]

Redthies, the whole truck is one giant mod really, it's put together from Ford parts spanning three decades: '90s DRW frame and rear axle, '80s sheetmetal and front axle, '70s transmission and t-case, all motivated by a mystery IDI engine. Slow and heavy but very reliable and hauls & tows anything we throw at it. Front actually rides quite pleasant as is, it's the rears that kicks like a mule when empty.

You bring up an excellent point with the air bellow failure. The front will not be an issue as those packs are and will remain 1-tons, but the rear would be problematic yes, very much so. So it's looking more and more like we'll do the 2-stage leaf springs, the 1/2-ton packs to carry truck empty and then trimmed 1-ton "overload" packs on top of them to carry the camper. Shooting for 2" lift (when empty!) at the same time, static in the rear via the leaf packs and dynamic in the front via air bellows. Will leave a few inches between the overloads and their frame brackets in order to avoid them "slapping" as the halftons cycle with no load. This will cause the rear to sag quite a bit when camper is loaded, but if geometry is thought out well enough then simply dumping the front bellows will bring the nose down and truck back into low-altitude level flight.

May still do the rear bellows (inboard of the leaf packs) just to be able to level truck with camper front-to back when parked, and also as a means of raising the rear in order to clear something like a fallen tree or whatever, but not as a primary load carrier. Sounds kinda silly but the air stuff is already paid for so no reason to just let it sit and collect dust on the shelf.

And if we can get our hands on a boom-truck rear sway bar, that would go on as well. Then we can remove the current 1-ton one as it cannot be quick-linked, while the boom-truck one can and will be. Mind you, we're not planning on taking this thing through rock gardens and such, just trying to make it slightly less specialized for one use only - so what if it takes say 10 minutes to disconnect the bars once we're off the pavement, we're gonna be crawling up the trail anyways (wheeling a dually presents certain challenges) so it's no biggie at all.

Helluva crazy plan, huh? lol

 

[redthies]

You're basic plan is sound. As you know, the risk/reward will come in the design and execution of the double leaf idea. I think it will work for what you want, and is a creative way to get the end result you want. Some pics of what and how you do, would be cool.

 

[coastal616]

I swapped the heavy springs from my 450 to some smoother riding f350 lift springs with Deaver mini packs. The ride is great, but it really squats with a load now. I'll be going with some Firestone bags that have about 14" of travel to supplement as needed. It's the only logical solution to ride quality and load carrying capability I can think of.

 

[superbuickguy]

The 1/2 ton leaf spring/air bags is exactly the set up I run on my truck. It works excellent... but why would you tie the two together? you'd go around a corner, the truck would push down one air bag... and inflate further the other.... quick way to lose control and potentially roll the truck. You do want to maintain equal pressure when hauling a heavy load, but you can vary the air pressure to compensate for disparate loads...

Before you put the 1/2 springs on your truck, though, make sure the sliders are in good shape and put white grease between the springs - otherwise they squeak in a most annoying manner.

As for your sway bar, I don't run a sway bar because I use mine for wheeling as well and I want the additional travel... with that said, I'm not sure why you'd disconnect it unless there simply isn't space to use it.

 

[1stDeuce]

I'd stay away from something like half ton springs, just because you have a LOT of axle to hold in place. Are you current springs old enough to have a boatload of leaves, or newer and with just a few? (Main spring, not the overload on top...)

If you have lots of leaves, you could consider pulling a few, or swapping to 3/4 ton springs perhaps. You might also do a quick ride with the rear shocks pulled. Sometimes the springs aren't the issue, it's the shocks. My truck's ride improved empty with about 10psi in the bags with the factory shocks, but it was very bouncy going down the road with the camper in the back and air pressure to level it back out. (30psi) I put some Gabriel Ultra shocks on and it rides awesome with the camper and same pressure now, but it kicks empty no matter what air pressure I run. That means my empty ride quality issue is now the shocks, but I don't drive the truck empty as much as with camper or something in the bed, so it works for me.

As for sway, I don't think you'll have any issues if you stay with a decent main leaf pack. My truck sways noticeably less with the bags inflated, but the AirLift 5000 setup I'm running only offers about 6" of total travel. That's the downside of aftermarket airbags for the heavier trucks. If I didn't have a B&W hitch, I'd consider running the half ton airbags for better travel. I've never put more than about 50psi in my bags, and that's to pull a 5th wheel with about 2500lbs of hitch weight...

 

[underdrive]

Redthies, yes, some careful planning and measurements will have to go into it. The basic plan is to either move the shackles down or use Sky's shackle flip kit, either way it's around 5-6" drop at the rear eye of the main packs, typically this would resulting in around 3" lift at the axle but the halfton springs being softer will probably flatten down some more so we'll probably end up with 2" lift which would be about perfect. Them being 2" lift springs to begin with will hopefully allow us to get rid of the current blocks altogether, but realistically we'll just drop the truck on top of the halfton leafs and see how much they flatten out and start figuring out geometry from there. And the overloads frame brackets will obviously need some reinforcing, but that's no big deal either.

Coastal, not sure how your Deavers are placed in your leaf stacks, but imagine your current 1-ton packs, 1" or 2" spacer, then your factory 450 packs (trimmed in length of course) on top of that, and that's what we're planning. Basically it will only squat till the top packs get in contact with the frame brackets, and that's about where it'll stay.

Superbuick, that is good to know the halfton/air setup actually works good. Have you hauled a camper in your truck, and if yes how heavy is it and how did the truck handle going around corners? The reason for tying the two bellows together is exactly the air transfer from side to side under load - this is a good thing when wheeling it, for driving on pavement there will be a valve in the middle of that line that when closed isolates the bellows from each other. Think of it this way, each bellow has its own feed/dump line, and then there is a bridge between the two bellows that will only be used when more suspension articulation is needed. So on pavement shut the bridge line off and enjoy individual bellows control from the cab, off pavement open the bridge line and let air move as it wants to and have the axle follow the terrain better. And yes the halfton packs will be cleaned, painted with farm implement paint, and the slider pads greased, we even have some extra slider pads in case we find some that are worn down. As for the swaybar, the reason for disconnecting it is exactly the same as why your truck doesn't even run one in the first place, but again this will only be happening when wheeling, on pavement bar will be hooked up properly. Bit extra work that way, but it's worth it.

 

[underdrive]

Deuce, the main springs have 5 leaves, not counting the extra-fat flat one on the very bottom which only purpose is to prevent the spring from arching the other way if overloaded too bad. It's a pretty standard setup for 1-ton trucks of the '90s, so can't do like on medium-duty or larger trucks and pull every other leaf out of the pack and still have a pack that's nice and even. IIRC the respective 3/4-ton truck has 4 leaves plus the flat one, the halfton is also 4 leaves but no flat one on the bottom. Thec shocks are likely not the issue, as we drove the truck without rear shocks (to the store and back) when we realized we were given the wrong set a while back, it was just as hard-hitting as it was before and as it is now, just way bouncier.

Air bellows we have have 9" travel for the double-convoluted ones and 14" for the triples. 7" diameter, actually makes them unsafe to run on top of the leaf springs as they would only have 1/2" clearance to the tire on one side and the frame on the other, way too close for comfort.

 

[1stDeuce]

Ok, so with the 5-leaf springs, you're probably not getting excessive friction damping like you would with 10 leaf or more packs of the '80's. I would honestly try pulling the shocks and take it for a drive again. Empty of coarse. Unless Ford really went overboard on the thickness of individual leafs, you really shouldn't have that much spring rate with the 5-leaf pack. If you find that it is still excessive, then some main springs from an F250 would be the next step, and if they're the same size otherwise (Length and width) then the F150 leaves might be OK too, particularly since you have the upper overloads for carrying the camper.

Give some stuff a try and let us know what does the trick for you!!