Shawn Snyder's "Tech Tips"
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Setting and tuning your race suspension at a glance
The first thing I do is check my tire pressure. This is one question that has many answers. I recommend running 10-12 psi in front tires and 7-9 psi in the rear, for larger tires. After setting tire pressure you want to check your tires footprint and make sure you have a good contact with the ground. All tires will vary on tire pressures; this is why it is important to check your tire footprint. If you run tire balls a good general starting pressure is 3-4 psi. Tire balls are used to keep your tires from going flat if punctured. Some pro riders use tire balls and they are commonly used in cross-country events.
The next step is to set your ride height. Make sure you have a level surface when doing this. I use weights to simulate the riders weight on the bike. I set my front ride height at 7 to 7 ½“ and the rear is set from 6 ½ to 7” for MX. For cross-country 8 ¼ in front and 8” in the rear is standard. Where you measure from is going to affect your results. I take my rear measurement just behind the foot pegs; the front measurement can vary depending on the bike. Most ATV frames have an upward curvature just behind the lower a-arm pivot points. You want to keep your front measurements as close to that curve as possible while still measuring from the straight bottom frame rail.
Setting the ride height on the front shocks first is a good practice. You add preload to raise ride height or decrease preload to lower ride height. Your “preload” adjustment can be present in different forms. For example, on Elka’s the setting is a collar with a setscrew that can be twisted up or down on the shock body. However on the HLS, PEP’s or WORK’s, the setting is a collar with a machined groove made for a clip that sits in another groove present on the shock body. For this adjustment, the shock springs and collar must be compressed revealing the clip. The clip can then be moved up or down on the shock body changing your peload. When setting the ride height in the rear you want to adjust your ride height very little with the preload adjuster. Most all factory and aftermarket rear shocks are adjusted by turning a collar with a setscrew up or down the shock body.
You must adjust preload from 1 to 3 turns compressed to achieve correct ride height. If you cannot achieve this, chances are you need a stiffer main spring. Having a low preload setting on the rear shock will decrease “bucking” and too much of it will cause the rider to go over the bars in a rough section. If you need more ride height and you’re out of range on preload, get a stiffer main spring and vice versa. Your springs will weaken in time and you will lose ride height as time goes on, that is why it is important to maintain your ride height.
The next step is measuring your rear race sag and how to adjust it.
You need to place your ATV on a stand so your tires are off the ground and the suspension is at full extension. You want to make a mark on the subframe with a sharpie anywhere directly above the axel. Then measure from the top of axle to the mark on the subframe. Remove the stand and get the rider on the bike, push down on the front and rear of the ATV a few times to allow tires and suspension to adjust, mainly the front end. Now replicate your last measurement measuring from the top of the axel to the very same location on your subframe make sure it is straight up from axle. You then subtract the compressed from the extended length and this is your race sag.
I generally see 4 to 5” depending on the application and the suspension components being used. You can make adjustments by turning the preload collar 2-3 turns or by changing the rear spring. You can make changes as well by using a heavier main spring to decrease race sag or soften main spring to increase race sag.
Next issue we will discuss the even finer points of correct suspension tuning. Good luck and thanks for a great season!
"Suspension Two"
Shawn Snyder
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