Nuts, I’m Confused
Q I’ve been a reader for over four years and have learned an amazing amount out of this magazine. I have a question about shock valving. What is it, and how does it work? I’m really lost when it comes to talking technical about shocks.
A Shock valving is the science of adjusting valves within a shock to better control the suspension. Shocks can have various types of valves, but most performance shocks have a valve or shim stack that controls how quickly or slowly the shock compresses and rebounds by controlling the oil flow through the piston of the shock. The piston is attached to the shock shaft, and the oil is encased in the shock body the piston moves though.
This all comes into play when you are driving over rough terrain. If you are driving at speed and hit a big berm and the suspension compresses too quickly, you can bottom out the suspension and cause parts to break. If the suspension compresses too slowly, the truck can buck and jump. The same goes for rebound, or the movement of the suspension away from the chassis. At slow speeds you may want the suspension to drop out quickly to keep your tires on the ground, or you may want it to droop out slowly so as not to push the vehicle off an obstacle during four-wheeling. The same applies for high-speed wheeling, where you want the tires to stay on the ground but not kick or buck over obstacles.
For the majority of applications, shock valving can be set at a happy medium and left alone for various terrains, but for extreme performance, such as competitive rockcrawling and high-speed desert off-roading, the valving can be very different. For example, the new trend of desert racing and rockcrawling combined has resulted in a challenge for shock tuners to get a middle-of-the-road valving that works well in both (though it’s rarely the best in either).
Adjusting your shock valving is a science that is tricky and requires a clean workspace to tear down and rebuild your shocks and lots of testing to get the vehicle to work just right. Many off-road race teams do “tuning sessions” in which they work with shock manufacturers to dial in their shocks for optimal performance. This involves hours of watching the vehicle work, removing, disassembling, and adjusting the shocks and retesting to see how the new tune improves the performance. Newbie shock tuners spend a lot of “let’s try this” engineering adjusting rebound and damping, but can achieve the same performance over time.
There isn’t an exact answer for what your shock tuning should be. Most manufacturers set the tuning based on what you tell them you are doing with the 4x4, and you can adjust from there.
Since your questions is an important one to many off-roaders, especially those who have invested in high-end rebuildable shocks, I’m giving you this month’s Nuts, I’m Confused prize, a set of Fox Racing Shox 2.0 Performance Series IFP monotube shocks. These aluminum-body shocks are valved for a specific application with a well-rounded valve tune, but can be disassembled and revalved if you’d like. These are direct replacement bolt-in shocks and are available for Chevy, Ford, Hummer, Land Rover, Jeep, Nissan, and Toyota vehicles. The 6061-T6 billet aluminum body caps and eyelets use polyurethane mount bushings and are black and clear anodized. Within the 2-inch body is an internal floating piston that separates the air charge from the oil to reduce frothing and shock fade at speed off-road. Fox Racing Shox has a full line of shocks for everything from mountain bikes to rockcrawlers and trophy trucks. Find out more at www.foxracingshox.com or by calling 800.FOX.SHOX.
Confused? Email your questions about trucks, 4x4s, and off-roading tech using “Nuts, I’m confused” as the subject and include a picture (if it’s applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I’ll be checking the forums on our website (www.4wheeloffroad.com), and if I see a question that I think more of you might want to have answered, I’ll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes. Write to: Nuts & Bolts, 4-Wheel & Off-Road, 831 S. Douglas St., El Segundo, CA 90245 fax to: 310.531.9368 Email to: email@example.com