3/4 Elliptical Suspension for Jeep Wranglers

A simple solution for more articulation Short Cuts
by: Randy Wheeler

Wanna get more flex out of your leaf-sprung rig?  Try this simple modification.

The 3/4 Elliptical Suspension

We all want more flex and articulation from our 4x4s.  That's just how it is.  Some of us go to great lengths to increase the amount of flex and wheel travel from our trail rigs.  Options out there range from doing custom spring over-axle swaps, coil conversion kits, shackle reversals to very custom reverse-arch spring conversions.  A new product has recently hit the market which allows for more wheel travel by way of installing custom shackles.  While all of these modifications will increase your articulation, some, if not most, are quite expensive.

Recently, I came across an article that detailed the installation of a 3/4 elliptical suspension on a leaf sprung Wrangler.  This simple, yet effective modification allows for more rear wheel travel and articulation, without taking a second mortgage on your house.  While other products on the market will provide additional articulation, I decided to install the 3/4 elliptical suspension on my 1991 Jeep Wrangler.



Parts:

The parts required for this modification are fairly easy to come by.  The only "custom" pieces you'll need are the u-bolts.  These were custom bent to my specifications using measurements taken from the frame rail width, height, and hole spacing on the stock spring pads. 

This is all you need!

My Jeep sports a Rubicon Express 4-in lift, 2-in Con-Ferr Extended shackles and a 1-in body lift, RS9000 Shocks and front extended brake lines.  The RE springs flex pretty good, but I still wanted more articulation. The 3/4 elliptical, or buggy leaf as it is often referred to, allows the rear springs to drop AND flex at the same time, effectively increasing your rear wheel travel by as much as 6 inches.  Not bad for a $60 investment!

Installation:

1 - Remove the center pin from the stock spring packs.
2 - Separate main leaf.
3 - Cut main leaf spring 5-1/2" from centering pin towards large bushing.  I used a hand grinder with a cut-off wheel for this. (see Photo 1)
4 - Drill a 3/8" hole 3" in from the cut end. This was a real bear, even on a drill press it took 3 bits and lots of elbow grease.  You may opt to drill a smaller hole for the centering pin.
5 - Jack up the rear of the vehicle and remove the rear wheels.   Support the vehicle with jack stands and chock the front tires.
6 - Remove the rear shackle from frame and leaf spring.
7 - Place the new spring under frame and align the bushing and original shackle mount vertically. With the spring cut at the proper length, the cut end of the spring should butt up against the support bracket on the frame.
8 - Support the spring plate and spring and mark the location of the u-bolts.   Note that you'll have to drill 2 holes on the drivers side and one on the passenger side through the metal plate on the inside of the frame rail.  The passenger side u-bolt only requires one hole to be drilled as there is enough room to bypass the plate on one side.
9 - Drill 9/16" holes for u-bolts.
10 - Install u-bolts over frame and through 9/16" holes. (see Photo 2)
11 - The centering pin location can now be drilled through the frame using a 1/2" drill bit.
12 - Place new spring against bottom of frame and put centering pin into 1/2" hole. A self tapping screw can be used to secure the spring plate/spring to the frame.
13 - Secure the spring plate to the frame using u-bolts. (see Photo 3)
14 - Apply lock-tite to the threads and torque the u-bolts to 90 ft-lbs.
15 - Re-install shackles.  I opted to use the stock shackles for this set up instead of using the extended shackles I had on previously. This gave me a pretty level stance in the rear.
16 - Repeat the process on the passenger side.

 

ellip1.jpg (14466 bytes)

Photo 1

Photo 2

 

Photo 3

 

Impressions:

At first I was a bit skeptical about doing this modification, but after installing it and testing it out, I have say that I really love it.  It does make the rear of the Jeep a bit bouncy on the road and I notice a bit more body roll going around sharp turns, but the increased articulation more than makes up for the on-road quirks.  As the above photo shows, this suspension modification allows for some cool articulation.

Modifications to the rear brake lines and emergency brake cable may be required.  With the 3/4 elliptical suspension and the stock shackles, an overall lift of approximately 1/4 inch was achieved, thus keeping the back of the Jeep level.  Had I used the extended shackles, the lift would have been more like 1.5 to 2- inches and the rear of the Jeep would have been sitting slightly elevated. 

Another addition that I'm considering is some form of limiting strap or u-bolt to keep the 3/4 spring from over-flexing during extreme articulation and either bending or breaking.

If you're looking for a simple, yet effective way to increase your rear axle articulation, look into this 3/4 elliptical suspension. 

Thanks  to Eric Barberly and Craig Meyers for providing the technical support and excellent photographs for this article.

 

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