Hanging the rear spring shackle from another leaf spring, NOT the frame. ideas?

**Big-n-Broke-YJ** · 08-31-2007, 10:46 AM

i was given this idea the other day and i think i'm going to try it....

rather than install my xj springs to my rear shackle hanger i should take one of the old main leafs i have and cut it about 12" from the spring eye.

then take that cut section of spring and flip it upside down

then bolt that through the frame

have the shackle at the end of my rear spring go to the bushing in this new addition...

while driving or compressing that side, the additional piece of leaf mounted to the frame would lay flat against the frame.

while dropping that side, the small piece of spring that had the shackle and my main leaf spring attached to would drop down off the frame for more droop....

i'll take pictures of what i plan to do and photochop some crap in there to try to make it clear what i'm wanting to try.

if you can picture this, do you know anyone who has tried this? i'm told it's not all that uncommon and i want to read up on it so i can figure out my shackle angles and decide how to modify the frame for that new leaf spring's mounting points.

-Erik

**Tomb Raider** · 08-31-2007, 10:53 AM

I would think you would almost have to weld it. The forces applied to that "extention" on the frame on droop would be severe. Not to mention when you drop it off a rock and land on the end of the leaf, inturn pushing up on that extention. If you sleeved the bolt hole and went through the frame to the top, I think you may be ok, but otherwise I would be concerned.

Mr YJ · 08-31-2007, 11:09 AM

What you are refering to is called a 1/4 elliptical spring extension.
This is what I think you're talking about.

No welding is necessary, a couple of spare springs, U bolts and some bushings
and you should be all set.

There's a good write up her.
http://www.4x4wire.com/jeep/tech/susp/3_4ellip/

91yjwrangler6 · 08-31-2007, 11:16 AM

so how tight do you have to make the u-bolts so that the spring doesn't pull ou of them? or is there really not that much stress on it?

grenMEG · 08-31-2007, 11:18 AM

Wow! thats nice!
I saw this once and i was thinking of doing it when i did my lift, but do you get insane wheel hop or does your rear end jump at all? what did you do to secure the 1/4 elliptical to the frame other than U-bolts? coule you run a bolt through your frame?

grenMEG · 08-31-2007, 11:19 AM

great minds think alike!

richmond1273 · 08-31-2007, 11:19 AM

i don't really know much about the system but awhile back i was reading a build article and saw this pic. i thought it was pretty smart of the guy to make the extra vertical brackets so he could put a pin through the bracket so when on road the extra leaf wouldn't come of the frame and when he went off road he would pull that pin and let it drop. i'm not quite sold on how he mounted it but i'm not sure how i would do it either.

**Tomb Raider** · 08-31-2007, 11:25 AM

While all of your responses are right....there is one thing not taken into consideration:

Since he would be using XJ springs, the back side of that would hang out beyond the frame about 6". That means, no support to that section like the ones shown above.

Mr YJ · 08-31-2007, 11:30 AM

Quote:

Originally Posted by Tomb Raider

While all of your responses are right....there is one thing not taken into consideration:

Since he would be using XJ springs, the back side of that would hang out beyond the frame about 6". That means, no support to that section like the ones shown above.

I would think a 3/4 box section welded to the back of the frame to his current / relocated spring mount would prevent the reverse bending you would see with it overhanging the frame [which is what I think you are concerned with]. You would lose ground clearance and departure angles though.

Everything's a trade off.

Edit: actually, you wouldn't lose any departure angle the more I think about it as it would still be within the spring packaging environment. It all looks good to me.

91yjwrangler6 · 08-31-2007, 11:36 AM

looks like a lot of work to me. would probably flex pretty crazy with xj springs if you could make it work.

**jbolty** · 08-31-2007, 11:42 AM

detailed writeup here:

http://jeep.undrground.org/tech/buggy/

93YJfalcon · 08-31-2007, 12:20 PM

Quote:

Ultimately, I decided that the Con's outweighed the Pro's and removed the springs from my Jeep. I am planning to go SOA, and didnt feel that the buggy springs would be needed anymore anyway.

Quoted from the link above. I've heard this complaint a lot with the 1/4th eliptical.

flame0086 · 08-31-2007, 12:31 PM

Quote:

Originally Posted by Tomb Raider

While all of your responses are right....there is one thing not taken into consideration:

Since he would be using XJ springs, the back side of that would hang out beyond the frame about 6". That means, no support to that section like the ones shown above.

I'm not an expert on XJ springs, but I don't think that would be a problem since you make the hanger no longer than the lenght of frame, right?

However, I would be concerned about the hanger sping being pulled out of the ubolt while the main spring is under load. If it were me, I would considering welding a stub on the hanging spring to go through the U-bolt.

**fratis** · 08-31-2007, 01:45 PM

this has been done, as per the pictures, alot in the past. the main problem is the single main spring is just that a single leaf. it pulls away from the frame first before the real leafpack flexes and droops and does what its supposed to do. they unload to quickly. in effect you have alot of droop happening at the mounting point of the one leaf and not enough on the mainsprings. not a really smart design in terms of durability. yes alot of people have done this and liked the results but also alot of people have rid themselves of it as well.

it would,however, be interesting to see someone build a variation on this. instead of using a sinle main leaf, use a few leaves like in a 1/4 elp. setup. the idea being the main springs do most of the regular work and only when the tire drops to its furthest do the "buggy" springs come into play. combine this with the xj rear spring concept and you would have something worth designing. i dont think you would need to extend the framerail out on the rear. it would just need a pad for the buggy spring to sit on.

**fratis** · 08-31-2007, 01:53 PM

Quote:

Originally Posted by Mr YJ

What you are refering to is called a 1/4 elliptical spring extension.
This is what I think you're talking about.

you are correct when you add the word "extension" to 1/4 elliptical, but for those who are unfamiliar with the terms it can be confusing.

its best to describe this as a 3/4 elliptical spring configuration. "buggy springs" are also a term used to describe the extra set of main leafs.

a 1/4 elliptical system uses only the buggy springs combined with link type axle locating devices.