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WHAT YOU DON’T KNOW ABOUT SUSPENSION

 
How to get the ride you deserve!

Ask the fastest racers, and they’ll tell you properly adjusted suspension is as important as all the horsepower in the world. Correctly tuned suspension makes any ATV easier to ride fast.

    Your ATV’s suspension is the key to making it ride as comfortably as possible and getting the most performance from it. When suspension is working its best, your machine will be simpler to control, more stable than ever—and easier to ride faster!
    Suspension on today’s ATVs is more adjustable than ever, which allows you to fine tune your machine’s feel and set it up to work well for a wide variety of terrains, riding styles and rider weights. So many adjustments are available on some ATVs that the whole idea of tuning the suspension can be confusing and intimidating, and some owner’s manuals are no help; they tell you to have your dealer adjust it! As a result, some riders never touch the adjustments and miss out on the amazing ride quality their machines can offer. In this guide, we’ll show you what you need to know to get the most from your suspension. We’ll be using a high performance sport machine for most of the examples in this article, but the basics of suspension tuning apply to all ATVs, from kids’ machines all the way up to the biggest 4x4s.
The latest high performance sport machines offer the most adjustable suspension; you can change the low speed compression damping, high speed compression damping, rebound damping, and spring preload. Shocks on some sport quads only offer adjustable compression damping rebound damping, and spring preload. Many models don’t have adjustable damping, only adjustable spring preload. Stock shocks on smaller sport ATVs and 4x4s also only offer spring preload adjustment, but this still allows you to tune the suspension somewhat. Some machines have non-adjustable suspension. Replacing the stock shocks with adjustable aftermarket units is the only way to change the suspension action on these machines.

THE STARTING POINT
    It’s important to know that stock ATV suspension is designed for a rider of average weight and skill, riding on terrain the machine was intended for. If you weigh considerably more or less, ride very aggressively or ride extremely brutal terrain, you may exceed the suspensions’ adjustment limits. If that’s the case, you’ll need to change the springs, shock valving, or the shocks themselves to get the ride and performance you’re looking for. Before you go to that trouble and expense, it’s well worth it to see what you can do with the suspension your machine came with and the adjustments it offers.
STOP! WHAT YOU SHOULD KNOW BEFORE YOU ADJUST YOUR SUSPENSION!

-Suspension components have a break in period just like the engine. New machines or new shocks may take up to five hours of riding to deliver the ride smoothness and compliance they were designed to. Avoid changing settings drastically until the suspension is fully broken in.
-Suspension components wear out, and won’t perform properly with worn or damaged parts, or if oil or gas pressure leaks out of the shocks. Shock oil also breaks down with use, so it’s normal for suspension to lose performance over time. Your shocks may only need fresh oil to work properly. If the shocks on your machine are rebuildable, your dealer or a suspension shop can do this for you.
-Shock oil is very temperature resistant, but it will thicken slightly in very cold temperature and thin somewhat at very high temperatures. You may need to adjust your suspension slightly for the temperature.
-Some chassis problems can feel like suspension problems. Worn or binding swing arm, linkage or A-arm bearings can hurt suspension performance and confuse adjustments. Tire pressure affects suspension performance, too. Set the tires to the pressures shown on the panel on the bodywork.
-Don’t mistake the nitrogen valve on the shock bodies on most ATVs for the air valve on an air shock. Nitrogen pressure is NOT a tunable feature used to firm or soften the action of the shock. The gas pressure, usually over 200 psi, keeps the oil under pressure so only oil without air bubbles passes through the shock valving to keep the shock action consistent. The shock will not perform properly if it loses nitrogen pressure.
SIDEBAR #1
STEP ONE: SETTING THE PRELOAD FOR CORRECT RIDE HEIGHT
    Most machines have spring preload adjusters on their shocks in the form of stepped collars or threaded rings on the shock body. This adjustment compresses the spring to adjust the machine’s ride height, which is how much the suspension compresses under the weight of the machine and the rider. Cargo weight can also affect ride height.
    Correct ride height is one of the most important factors in getting your ATV to handle properly. Basically, you want to adjust preload so the rear suspension compresses or “sags” roughly one fourth its total travel under the rider’s weight, but no more. This makes the machine ride level with the rider aboard, which helps it steer and respond properly to bumps. Too much sag reduces the suspension travel available to absorb bumps, and can allow the suspension to compress into the firmer part of its travel, which can make the suspension feel harsh.
    If you can’t adjust in the correct amount of sag with the preload adjusters, the shock springs are too soft or too firm for the rider’s weight.


Spring preload adjusters on most competition machines are threaded rings on the shock body. If you can’t arrive at the correct amount of sag for the rider’s weight with the adjuster fully tightened, the spring(s) are too soft. If you can’t get the correct amount of sag with the adjuster backed out all the way, or at the softest “step”, the spring(s) are too firm.


Many ATVs, including most 4x4s, have stepped preload adjusters that are best moved with the special wrench supplied in the machine’s tool kit. You can turn these adjusters with Channel Lock pliers, but the shock’s appearance may suffer.


A few minutes setting the spring preload can improve the ride and handling on utility ATVs. Increasing the preload can reduce the body roll that spoils the cornering feel on sport utility ATVs, especially models with independent rear suspension (IRS). If you’re carrying heavy loads on the racks, adjust the preload to level the machine. It will handle better.

STEP TWO: COMPRESSION DAMPING ADJUSTMENT
    Once you’ve set the spring preload and determined that your machine’s springs are correct for the rider’s weight, you can deal with two of the most common suspension problems, excess bottoming and suspension that feels too firm. More compression damping will make the suspension firmer and help it resist bottoming. Reducing compression damping will soften the suspension and allow it to bottom more often. Correctly tuned suspension uses its full travel and bottoms occasionally.


On most front and rear shocks, the compression damping adjuster is a screw on the shock body near the top shock mount. Turn the screw in fully, being careful to count the number of turns needed until the screw stops. Some shocks have detents on the adjuster screws to help you count the adjuster positions. When the screw stops, the compression adjuster is set at its firmest setting. If your suspension bottoms too much or feels too soft, test ride the machine at this setting, and back the adjuster out one turn or click until you find the combination of bottoming resistance and firmness you’re looking for. Be sure to put both front shocks at the same setting.


HIGH SPEED COMPRESSION DAMPING ADJUSTMENT (HSCD)
    Shocks on some machines have separate high and low speed compression damping adjusters. The HSCD adjuster controls how the shock responds on impacts that generate high shock shaft speeds, like jump landings, square edged bumps or rocks. This adjustment is important for proper suspension performance for riding at all speeds, because it relates to shock shaft speeds, not how fast you’re riding.

LOW SPEED COMPRESSION DAMPING ADJUSTMENT (LSCD)
    LSCD controls how the shock compresses on impacts that generate relatively slow shaft speeds, like rolling whoops.  Like HSCD, adjustment this setting relates to shock shaft speeds, not how fast you’re riding. Most shocks with separate high and low speed compression damping adjusters use a screw for LSCD adjustment. Turning the screw clockwise firms the LSCD so the shocks use less travel on whoops and rolling bumps. Turning the screw counterclockwise softens the LSCD.

REBOUND DAMPING ADJUSTMENT
    Rebound damping adjustment controls how quickly the shock extends after a bump compresses it. Many riders adjust the rebound incorrectly because suspension “kick” can create the impression that the suspension is rebounding too fast, when it is really rebounding too slowly and “packing down” which keeps the suspension in its firm, final inches of travel so it can’t absorb the next bump without kicking. It is helpful to test with a wide range of rebound settings and have an observer watch how the suspension responds before settling on a rebound setting.


On most shocks, the rebound adjuster is a screw located near the bottom shock mount. Turn the screw clockwise to make the shock rebound slower. Turn the screw counterclockwise to make the shock rebound quicker.



Comments:
Saturday, January 12, 2013 8:52:31 PM by trx450rmx
My low compression adjustor stopped clicking when I adjust it no matter which way I turn it. What does this mean? Did this happen becuase I put WD-40 on the adjustor so it would turn easier?

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WARNING: Much of the action de­pict­­ed in this magazine is potentially dan­gerous. Virtually all of the riders seen in our photos are experienced ex­­perts or professionals. Do not at­tempt to duplicate any stunts that are be­­yond your own capabilities. Always wear the appropriate safety gear.
Copyright 2012 Hi-Torque Publications, Inc. All rights reserved.
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