Rancho Shock Selection Guide

This data came from the Rancho Shock Selection guide on ORC. I found and corrected a few typos in that data, grouped it by similar mount styles and finally sorted that by travel. Within a given shock style, you can search for the desired amount of travel then cross reference that with the various model numbers. Alternately, use your browser's "Find in Page" feature to find the line for a given shock model. I have also embedded tags for each shock model number, so you can jump directly to a given model by just typing in the URL for each model, e.g.for RS9012 enter: #RS9012

• There is also another Rancho shock page on GeoCities
• Rancho has a web site with some product information
  • Note: Rancho shocks are manufactured by Tenneco Automotive, same company that makes Monroe shocks, as well as Walker and Dynomax exhaust systems
• The Rancho/Australia site has additional technical information
• ORC has a good writeup on determining shock absorber lengths
• My Ramp Travel Index page has some tips for suspension measurements as well

Shock Mount styles:

EB1 : Loop - 5/8" inside dia.

EB2 : Loop - 3/4" inside dia.

EB4 : Loop - 11/16" inside dia.

ES25 : Loop - Similar to EB1 but also has a removable metal bushing

ES113 : Loop - 16mm inside dia.

S1 : Pin type mount

Note: It is fairly easy to swap bushings in Rancho shocks. You can buy bushings separately and then press out the old bushing and replace it with a different size or composition bushing.

Also, I've modified bushings to suit my needs, opening up a 5/8" EB1 to a 3/4" hole with my die grinder

Hint: Drilling won't work, the polyurethane just stretches around the drill bit, unless you put the bushing in a deep freeze (below 0F) for a few hours, then check the bushing up in a lathe, spin it up and run a drill bit through quickly before the poly warms up.

• Shock Families:
  • RS50xx-series:
    • Non-adjustable
    • Black rubber bushings
  • RS9xxx-series:
    • 5-way adjustable, single-shock valving?
    • Red polyurethane bushings
  • RS9xxx-series:
    • 5-way adjustable, dual-shock (soft) valving?
    • Red polyurethane bushings
  • RS9000X series (p/n is indicated as RS99xxx)
    • 9-way adjustable
    • Red polyurethane bushings
    • See: http://www.gorancho.com/documents/RS99000Interchange.PDF for interchange data
      • Indicated on the tables below with a red X

Color Coding:

Red - Stock Length for 1st generation 4Runner ('84-''85 front, '84-'89 rear)

Boots:

Rancho shocks come with red accordian-style boots to cover the extended rod. While many people install the boots because the look cool or perhaps because they think the boot will protect the polished and chrome plated rod from damage, in fact the reverse is often the case. The boot can trap moisture inside it which can lead to the rod rusting which in turn destroys the seals inside the shock body itself, leading to failure. I've never seen an exposed shock rod get pitted or scratched from gravel and mud, but every booted shock I've seen has heavy layers of rust on the normal unused part of the rod. However, hit that one big bump and jam the rusty rod into the shock can and that may be the end of the shock.

Mounting:

Can up or can down? The RS5xxx shocks are apparently supposed to be mounted can-down in order for internal valves to function properly. The RS9xxx shocks are recommended to be mounted can-down, but will work can-up, too. Can-up mounting has a number of advantages:

Less unsprung weight, as the can/valves/oil reservoir is attached to the frame and not the axle

Less chance of can damage, as it is up and away from trail hazards

Remote control air hose routing is easier as the attachment point does not need to move

When I ran RS5xxx, I ran the can-down and had no problems. With the RS9xxx, I had one shock fail after a few days of use in a can-up position. I think this was a mfg. defect as the other shock was fine. I've since been running my rear RS9xxx shocks can-up with the remote control setup and they work just fine. My fronts are mounted can-down because of design constraints of my long travel shock setup.