Shortly after buying the truck, I installed the Rancho add-a-leafs that provided about 2.5" of lift. The problem with this setup was that it was extremely stiff, uncomfortable, and had poor travel.

I found when using the Downey springs that I could no longer touch the bump stops on the rear, even with the truck severely twisted up. Downey insists that the thick factory steel load leaf be used on the bottom of their spring pack to prevent the spring from bending backwards.

It is this load leaf that was limiting my compression travel. Removal of this lower leaf allowed for several more inches of compression travel and also lightened the spring rate somewhat, making it more supple for rockcrawling.

Flatter springs offer greater droop capabilities than those with more arch. But......due to the frame and spring mount design, Toyota trucks must run fairly deeply arched springs. To increase my droop capabilities, I needed a rear spring that was longer. Custom springs are expensive and if you don't get exactly what you want the first pass, the final price goes up even more.

The solution I settled on uses a set of modified Mazda 2WD truck springs and new forward mounts on the frame to accommodate the longer springs. Rear truck springs are approximately 47" long (arch length) and the Mazda springs are almost 52" long.

Toyota truck springs also have the center hole offset such that the length of spring behind the hole is about 4" longer than the length of spring in front of the hole. The Mazda springs have the hole much closer (about 1/2" offset) to the center of the spring.

As such, it was possible to mount up the Mazda main leaf without moving the center hole, and leave the rear shackle in the factory location on the frame. The only modification needed was to provide another forward mount on the frame, forward of the original one. A new pair of spring mounts was purchased from Toyota, modified slightly, and welded onto the frame.

The original mounts were left in place for several reasons. Leaving the original mounts on provided for reversibility, and attempts to remove such mounts from another frame had proved to be very difficult. Once the new mounts were welded to the frame, a 3/16" steel plate was added to the side of the mount connecting the old and new mounts together. This plate simply bolts in place using the old and new forward spring bolts.

This provides a small improvement in strength, but mostly provides for a cleaner look. Finally, the holes in the newly added mounts were drilled to accommodate 5/8" grade 8 bolts.

A total of four Mazda spring packs were purchased, and they were modified to increase the spring rate and increase the arch slightly. Leaves were mixed to build the following spring pack:

This pack provides about 3" of lift (over stock) when combined with the approximate 1.5" of front mount drop (due to the new location of the new mount), and a 2" longer than stock shackle. Based on your desired spring rate and lift, you can build a spring pack to suit your needs.

With this spring configuration, vertical travel movement has been increased to 13-14". Rancho RS9012 shocks were installed during the spring swap. The lower shock mounts were reused, but new custom upper mounts were required.

These new mounts were placed up higher towards the bottom of the bed and were moved forward/backward to lay the shocks down slightly more. Rubber bushings were used to allow supple movement at the shock eyes.

Depending on your current setup, extension of the brake line and cable(s) may be necessary due to the increased droop capability. Also, depending on leaf pack thickness, new u-bolts may be required.