Allright, since my truck was stolen I've decided that it's time to go in two totally different directions at once. First off I'm making my new DD into the best pavement/tow vehicle I can.

Secondly, It's time for me to start planning for my next play toy.

My plans are to start with an 80-96 Ford frame and mount the cab from my last truck. From there I'd cut the frame off about 2' past the back of the cab and run a 1/4 elliptical setup.

What I'm planning on is using the spring packs in double duty, as springs and as lateral locators. Then all I'd have to do is build lower links to control pinion angle and suspension load up.

I'm looking for ideas on how to execute this setup. Most pictures I've seen seem to use lower and upper links along with teh springs.

I'd think it'd just be that much more work and materials to try to get 6 links to all move in the same arc instaed of just 4.

I'm going to go look around Pirate some more, but figured I'd ask here just to see what anyone had to say.

Justin

 

first off... long time no see! good to see you are still poking around.

secondly... holy cow, your rig was stolen? didnt know that? whats the story? did you burn his house down after you found out who it was?

thirdly... to the tech part of this post, thats a lot of responsibility to put on the springs. i imagine there is a reason its hard to find a setup like you are talkin about. i'll see if i can dig up some stuff from my computer at home tonight as i was thinking hard about doing this

-cutts-

 

Yeah, i poke around time to time.

The truck was stolen about 2 months ago. I'd swapped in an FE 390 and had all the body work done when someone (still dunno who) decided he liked the truck more than me.

The guy only made it about 10 miles before he drove off a T in the road doing about 65 mph. took out a 10" cedar tree, a 6" oak, a 8" oak, bounced off a 14" oak, and left paint marks 7 1/2 feet up the side of a 24" oak. It was quite the scene.

Dunno who it was, but from the blood and the internal damage to the cab he wasn't feeling too good.



Anyways, back to tech.

I figured out why the 1/4 elliptical typically uses 4 links plus the springs. People either shackle or heim the springs to the axle housing to allow more flex. Therefore the springs can't act as locating links.

I'd have to directly mount the springs to the tube to get them to act as lateral locators which would be fine for a streetrod, but not for something that needst o twist up.

Justin

 

That set up is just not all that popular anymore. There were plenty of trucks trying it, but there were all kinds of limitations. Super long leafs were used to maximize flex, and the trade off was body roll, and the tendancy to flip over.
If a multi link suspension is going to be used, the coil over is a much better choice. The coilover is much easier to calculate the rates to increase progressively and obtain more stability. Also gives you the option to run a dual rate, or even tripple rate springs.
Heak even the air spring from Fox, Sway-Away, King, etc is super cheap.
Either way it is going to need a sway bar, but man the flex will be out of this world, and considerably more usable than any eliptical set up.

To bad about your ride. Having stuff stolen is pretty low.
Ever find the guy after the bloody mess?

 

People keep telling me to go coil over or air shock or what have you, but the truck will never see pavement so stability over about 20mph isn't that big of a deal. I've also seen plenty of people that claim their 1/4 elliptic is perfectly stable to faster than their willing to drive their buggy.

when it all comes down to it, there is no difference between a 4 link 1/4 elliptical and a coil sprung 4 link. the only difference is the style of spring. It doesn't matter if you use super long leaves for the 1/4 setup so long as you set it to an appropriate spring rate.

The only drawback I see to a 1/4 setup is that it isn't super super easy to determine a spring rate without actually testing springs. BUT, it is easier to vary the spring rate of a 1/4 setup through simple things like spring pack clamps instead of having to totally swap out coils.

So all at once with enough time and testing a 1/4 elliptical setup is just as effective as a coil sprung setup and looks that much cooler

I'm also not going with an airshock since i don't know how much this thing is going to weigh in the end. Fox rate their to 1,000 lbs each which would be fine in a tube based competition buggy, but in a fullsize based play toy with god knows how many tools and spare stuff, i don't know if i'll be able to keep it to 1,000 lbs sprung weight per corner.

And honestly I'm wanting to go 1/4 elliptical because it's seen as being a "difficult" suspension to figure out. I have plenty of time and would rather do for myself than duplicate a coil or coilover setup that 1,000 other people are running right now.



Justin

 

i dont know anything about the setup your trying to run but i have to say go for it even if its not conventional. dont let anyone change your mind its so much funner to think outside the box. thats why im researching and building very soon the turbo setup i am everyone tells me not to do it do it this way and i cant. too many people already have. why build something everyone else has when you can build something that makes people go what the hell is that, exspecially if it works great.
good luck outside the box!!!!


tony

 

The stability is more for "off camber" hills, and negotiating big obstacles with one tire, or one side of the truck, and not necessarilly highway stability.
The length of the spring will determne the amount of movement the axle can have. You also have to remember the amount of spring cycles the spring will have is greatlt decreased and these style suspensions twist the leaf. The leaf was never intended to twist much and it will eventually break. Many eliptical set-ups die as a result of spring fatigue.
Leafs are also pretty heavy when compared to anything else, but hey, that's what makes wheelin that much more fun. Different combo's make it that much more fun.
Hope it works out for you.

 

And again, stability is more of a function of spring rate and traction than the length of the leaves.

As for the springs twisting, yes they do but there are ways to alleviate it. Instead of running plain bushings, a spherical rod end at the axle housing would definitely get rid of the first chunk of spring twist.

So yes, these are all obstacles that need to be overcome but i'm not terribly worried. By the time it's ready to be run it'll be a fully exo-caged truck based buggy. I'm building it to not have to worry about dumping it on it's lid while i'm sorting everything out.

Justin