how to combine spring packs

[That_4.0_ranger]

so i have two sets of ranger leaf springs and i was wondering how to combine them to make them stiffer has anyone done this?

 

[sgtsandman]

The leafs need to be progressively shorter as you build them so that the lower leave slides along the upper one.

I can’t tell you what the proper lengths would be. You will also need a keeper (probably not the right name) that will fit over all the spring to keep them stacked on top of each other.

The center bolt that holds everything together and locates the axle should be easy enough.

 

[don4331]

@sgtsandman:
I believe what you are referring to as a keeper is called a rebound clip. It's primary purpose being to keep the leaves in contact during rebound (leaves separating and then coming back into contact with impact being very bad for leaves). The secondary purpose being to keep all the leaves pointed in right direction, so they work as they are supposed to.

The ideal shape from a theoretical point of view is an octahedron (i.e. 8 sided dice), but that would be very difficult to manufacture/install. So, polyhedron is approximated with a number of progressively shorter rectangular leaves.

So, for our example, we start a 2.5" wide strip of steel .25" thick, 56.5" long and bend it to an inside radius of 40". Then we take strip 46.5" long and bend it to inside radius of 40.25". Then we mate the 2nd leaf to the 1st, nothing that the inside radius of the 2nd leaf exactly matches the outside radius of the 1st (inside radius of the 1st + material thickness). Repeat for as many leaves as you have.

1st leaf is a little longer as there are eyes bent into the ends, ends of the 2nd leaf get "trimmed" to better approximate the theoretical.

@That_4.0_ranger

So, if you add a repeat of the 2nd leaf to the existing pack. a. The curve of the new leaf doesn't match the curve of the previous leaf - you would have a gap in center. Now, when you install/tighten the center bolt, you can remove the gap (you actually have to for the spring to work correctly), this will result in you will increase the camber (height) of the spring pack (over what your are adding for the actual leaf thickness as when you pull the new spring against the previous 2, it will force them up). b. You are also preloading the spring, so it won't flex over small bumps = rough ride. c. You are creating a stress concentration on the leaf above - both the 2nd and new leaf at the same point. c. you will need new rebound clips to keep the leaves in contact.

If you understand the drawbacks, it is possible. I've never done it for a Ranger, but I've done it.

Note: It isn't going to increase the LEGAL load carrying capacity; that was determined by Ford on the Federal sticker.​