air springs and camper hauling

[Sooper Camper]

my 2 cents for what it is worth:
air bags good, tied together not so good. keep them independent, it will drive better; you don't want a spring rate that changes constantly depending on the attitude of the vehicle. also think leak or failure mode, if linked...one loses pressure they both lose it

if you are running the standard 3" wide x 57" long springs, you will need to find a bronco if you want lighter springs. the bronco springs actually have a pretty good spring rate. Personally, I would mix and match until you have a custom pack...maybe keep the F350 main leaf with thinner bronco leaves underneath (i cut the eyes off a main leaf and added it under the actual main leaf on my old bronco for a little lift and increased spring rate).

The thing to watch out for will be axle wrap. Sure, you can strip all but the main leaf out and hold it up just with air bags if you really want to, but the main leaf will twist like a noodle under load. Half ton springs are very light rate compared to 3/4 and 1 ton springs, and they will twist under high load/traction. You can get creative too, like chopping a main leaf and adding it above the actual main in the pack to prevent wrap without adding too much spring rate.
Here is what I started with on my 1 ton. It rode like a tank, and had almost no usable wheel travel:

Here is what I ended up with:

All I really did was pull 2 of the shortest leaves out as well as the flapper leaf, flip the lower overload upside down to let it have a little more compression travel, and I took the second longest leaf, chopped off the end aft of the center bolt, and stuck it on top under the spring clamp. It fights axle wrap but doesn't really add any spring rate to the pack.

The truck now squats a bit more under load, but at the same time it doesn't jar my kidneys driving around the block. I could put the upper flapper leaf back in with an hour of wrench time to help with the squat, or eventually add airbags. This is 2+ yards of wet fill dirt, and even though its on the bumps it drove fine the 15 miles back home:

 

[underdrive]

Deuce, pulled shocks again - same as I remembered it, Hendrickson rubber blocks ride smoother. One would think 5 leaves shouldn't be that bad, but it is. Most older F-series use the same length/width springs, only exceptions are 2wd F150s and cab-chassis F350s which got 2.5" wide packs instead of the more common 3" wide. Springs we have are 2" lift for a 4x4 F150, so should be direct bolt-on in place of the 1-ton stuff. Minor snag would be the front eye bolts (9/16" for halftons, 5/8" for 3/4-ton and up) but since we're redoing the bushings with poly anyways we'll just use an inner sleeve for a 1-ton truck.

Sooper, mixing and matching leaves in these particular main packs would not be a good thing, reason being the halfton packs have way more arch to them than the 1-tons so they won't play nice together. You do bring a good point about axle wrap, I thought I already covered that earlier but I guess I didn't - we're not too worried about that as it is mostly noticeable under heavy load, which will also cause the suspension to sag and the overloads to start doing their thing, at which point the overloads will handle axle wrap as well. The only other situation would be trans in 1st gear and case in 4-low, but in those conditions the front axle is pulling just as hard as the rear is pushing so overall there shouldn't be much wrap. Your idea of the half-leaf on top of the main packs is quite interesting, IIRC we should have some F450 overload leaves laying around that could get sacrificed for that and should work quite well. Do have a question though, why did you point your half-leaf forward? When the axle wraps while attempting to move truck forward it twists towards the rear (pinion yoke climbs up), this would force your half-leaf to attempt to separate from the main pack - are you relying on that clamp to hold it in check? How about flipping it around so it points at the shackle end of the main pack, that way when the axle wraps it will try to force the half-leaf into the main pack. That does, however, load the half-leaf in the wrong direction, so maybe forward mounting with a clamp like how you did yours would indeed be better... Gonna check tomorrow if the halfton leaves have provisions for said clamps.

BTW regarding the air bellows, I've had the lovely experience of one side letting go with no warning, I'd much rather deal with both purging at the same time and dumping the axle straight down onto the bump stops than have a single-side failure that all of sudden induces massive roll towards that side. Non-isolated bellows sure do make for some boat-like drive though.

 

[Sooper Camper]

Most of the newer spring packs do not have the nicer removable clamps like the old trucks. Yes, the half leaf engages the clamp. All the high-end spring packs have the wrap leaf up front, they usually do it by wrapping around a military style eye. With a leaf spring, the twisting motion is really only acting on the front half of the spring; the rear half is along for the ride. By putting it on the front half of the spring, when the axle wraps it engages the wrap leaf and adds spring rate to the front side to counter it, without grossly affecting the overall spring rate of the pack (compression force from the wheel affects the whole pack). It also becomes neutral on the droop side, as it is pretty much floating until the springs bind at full droop. The way I accomplished it is just a ghetto (read: free) way of doing what a high-end military wrapped spring usually does.

 

[chilliwak]

Underdrive, I personally would stay away from the half ton springs and air bag set-up. The guy that does my springs is a true 4x4 enthusiast, and he says that airbags are fine on the highway, and useless offroad. They cant hold up to the punishment. I have rear springs with a huge pack and a huge arc. The truck can go almost as fast on a logging road as on pavement. I use a rear sway bar and some good Bilstein shocks. Like you I have a big camper with the sway that can come with such a beast. Check out my build thread for more info. I hope this helps. Cheers, Chilli...

 

[100acrehuphalump]

You guys ever hear of this product? It claims to cover all aspects of suspension upgrade and any issues involved.
They claim to reducing vehicle sway
Reduces dangerous roll in cornering
Axel wrap and wheel hop
Eliminates bottoming out
Improves hard braking, and acceleration
"" stability in cross winds
"" towing and load carrying capability
"" driver control and driver control with a load
Minimizes headlight dazzle. Whatever that means
Prevents a harder stiffer ride.
I'm interested and the place that fixes my tractor tires swears by them, and claim to use them in all of their service trucks. They say to use these instead of airbags. I'm about to buy a FWC Hawk for a F150 half ton. I'm a noobie in all of this suspension stuff sooooo any thoughts? No I'm not affiliated with either the tire place or the Roadmaster.

http://www.activesuspension.com

 

[underdrive]

SooperCamper, got it, makes sense. We have extra leaves, so we may copy what you did to your suspension.

Chilli, good to know! Our offorading is usually rather slow-paced mostly due to size of truck and width (or really lack thereof) of trails, but the air bellows are not commercial-duty monsters either. Alright, looks like we'll be going with all-springs for load carrying and stability with inboarded air assist (since we already have the components) for leveling when parked and occasional on-demand lift for departure angle purposes. We'll take a look at your build thread, actually I'm pretty sure I've already read it, but I don't recall the springs, so now we have some specifics to look for.

100acrehuphalump, I recall seeing that website before, however we do not know anyone using that setup, so I cannot tell you yay or nay on it. The advantage of air bellows is that your ride height does not change (or you can change it however you please), with the RAS you will get some sag into it before it settles where it wants to sit. So in a sense it will act like somewhat like a standard overload leaf, but without the nasty slapping if your load is just heavy enough to make the overload touch its pads at rest but not heavy enough to force it firmly against said pads. In our case the truck sees pretty much just two loads, empty and maxed-out GVWR, so we don't get the slap. Another thing to consider is that with standard overload leaves or air bellows you gain more points for the load to transfer between frame and suspension, meaning the spring and shackle pivots get to live a bit easier life - with the RAS all the load is on the spring and shackle only, which other than accelerated wear on the bushings also means that should something let go there is no contingency in the system, the whole side will drop. Which I've had happen when an air bellow went poof, not fun at all, even with tandem axles. For a halfton truck with a lighter camper it may be just fine though, but with our monsters we like spread loads and somewhat of a built-in plan B (and, with the air assist, technically C as well).

 

[underdrive]

Oh, while I remember, what's everyone's opinion on rear shackle flips with a heavy load above them? Obviously going to need some heavy-duty shackles, as factory stuff is designed for tension loads and not compression. Choices are pretty much Sky's kit with some F450 shackles, or RuffStuff's universal kit. Trying to get the tail end of the rear springs down so the whole spring sits more level, this will make it absorb road impacts better and hopefully allow us to get rid of the axle lift blocks.

 

[Sooper Camper]

personally, i would stay away from a shackle flip for what you are doing. a tension shackle is more stable and resists hop and wrap better IMO, especially with "spring over" type configuration. I did the Sky kit on my 89 Bronco, it was a well made bracket and installed just fine. But that truck developed pretty bad hop after I did the flip and only cured it by adding a set of ladder bars. The newer Dodges use a compression style shackle and seem to do OK, it really comes down to spring pack and shock valving more than anything.

It sounds like you need to just bite the bullet and get a custom spring made, funny thing is they really aren't that expensive if you aren't making a race pack.

 

[100acrehuphalump]

You guys ever hear of this product? It claims to cover all aspects of suspension upgrade and any issues involved.
They claim to reducing vehicle sway
Reduces dangerous roll in cornering
Axel wrap and wheel hop
Eliminates bottoming out
Improves hard braking, and acceleration
"" stability in cross winds
"" towing and load carrying capability
"" driver control and driver control with a load
Minimizes headlight dazzle. Whatever that means
Prevents a harder stiffer ride.
I'm interested and the place that fixes my tractor tires swears by them, and claim to use them in all of their service trucks. They say to use these instead of airbags. I'm about to buy a FWC Hawk for a F150 half ton. I'm a noobie in all of this suspension stuff sooooo any thoughts? No I'm not affiliated with either the tire place or the Roadmaster.

http://www.activesuspension.com

Found out they're not a good purchase, so nevermind!

 

[underdrive]

personally, i would stay away from a shackle flip for what you are doing. a tension shackle is more stable and resists hop and wrap better IMO, especially with "spring over" type configuration. I did the Sky kit on my 89 Bronco, it was a well made bracket and installed just fine. But that truck developed pretty bad hop after I did the flip and only cured it by adding a set of ladder bars. The newer Dodges use a compression style shackle and seem to do OK, it really comes down to spring pack and shock valving more than anything.

It sounds like you need to just bite the bullet and get a custom spring made, funny thing is they really aren't that expensive if you aren't making a race pack.

Yeah, we're aware of the inherent stability of the tension shackle setup, just not crazy about the factory rear geometry - if the spring sits flatter (the two eyes are closer to level) then any impact coming from the front will tend to also induce an upward motion of the axle, which is helps ride quality. The way it is now the axle pretty much only moves up-down, but especially with the factory blocks it's sorta fighting itself. There's no easy way to move the rear eye down and keep tension shackle though - we've seen some people move the shackle hangers down on the trailer hitch (with proper plating of course), but ours doesn't reach far enough. Well, there is a fuel tank down there, and it does need some protection - can always build a cage for the tank and tie it into the hitch in the rear and the frame in the front, then hang the shackle hangers off that... That could actually work rather well.

New springs are always an option, we just wanna see if we can pull it off with what we got. If it doesn't work out throwing in a custom-leaf setup is easy enough. It's the whole "built not bought" thing, sometimes it doesn't quite pan out but won't know unless we try

 

[underdrive]

Found out they're not a good purchase, so nevermind!

Interesting, why is that? Any inherent problems with the design? Or just not going to work well for your application? Curious minds wanna know

 

[Sooper Camper]

There is some really good information in here, even though it caters to circle track, that helps to explain why I'm not a huge fan of shackle flips. Its more than just my anecdotal evidence that they increase wheel hop. Check out what lowering just one eye and flattening out the spring does to your roll center; lowering roll center in relation to vehicle COG increases body roll. I also find it interesting that most semi trucks don't use a shackle on their drive axles if they run leaf springs, they just use a form of slider. If you look at the picture titled "2nd Shackle Effect", you'll see that as a compression shackle moves it loads and unloads the spring...a tension shackle does the same thing but in the inverse. Regardless of how you decide to go with your truck, its worth a good study to help explain the mysteries of leafs. They are IMO one of the single LEAST understood aspects of vehicle dynamics.
http://www.bedfordspeedway.com/toolbox_leaf.htm