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    • Bryan Bosch

      JUST IN!   04/24/2018

      HOW TO: 4-STROKE PISTON REPLACEMENT DONE RIGHT!
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Set Your Sag


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Race sag is the distance the suspension sags under the combined weight of the bike and rider from its fully extended (topped out, no load) position. If your race sag is correct, your suspension is in the middle of its range, where it can handle the widest range of riding conditions without topping or bottoming out. For most riders, a race sag of 90-100 mm translates to the correct preload for dynamic conditions.

Static sag is the distance the suspension sags under the bikes weight alone, without a rider, from its fully extended position. Once you get your race sag correct, the static sag will tell you whether or not you have the correct spring for your riding weight. So always check static sag after setting your race sag, because the preload adjustment affects both.

STEP 1 => Put your bike on a stand, and measure the vertical distance from the rear axle to a spot on the rear fender. Record this value as M0…

PIC-1.jpg

STEP 2 => Take your bike off the stand, put on your riding gear, take a standing position, and measure again. Record this value as M1…

PIC-2.jpg

STEP 3 => Subtract M1 from M0… this is your race sag. If it’s between 90 and 100mm, skip to Step 5. If not, put your bike on a stand, lubricate the threads on the body of the shock, and proceed to Step 4.

STEP 4 => If your race sag in Step 3 was significantly less than 90 mm, decrease the preload by moving the rings up the shock body (ccw). If it’s significantly more than 100 mm, increase preload by moving rings down shock body (cw)… Repeat Steps 2 through 4 until race sag is between 90 and 100mm, then continue with Step 5.

PIC-3.jpg

STEP 5 => With your race sag now correct, and your bike off the stand, measure again, but this time with the bike under its own weight. Record this value as M2…

PIC-1.jpg

STEP 6 => Subtract M2 from M0… this is your static sag. If it’s between 25 and 35mm, your preload and spring rate are correct. Take your bike out for a test ride, then come back to this forum, and do “Adjust Your Dampening.” If your static sag is not between 25 and 35mm, proceed to Step 7…

STEP 7 => If your static sag is less than 25 mm with the correct race sag, your spring is probably too soft for your riding weight. What happened is this: to get your race sag correct, you set the preload higher than it would have been with the correct (stiffer) spring. So the bike sags less than the recommended value under its own weight. If your static sag is more than 35mm with the correct race sag, your spring is probably too stiff for your riding weight. What happened is this: to get your race sag correct, you set the preload lower than it would have been with the correct (softer) spring. So the bike sags more than the recommended value under its own weight. In either case, go to www.racetech.com, and checkout the recommended spring rates for your bike and riding weight. Buy the spring and install it, then recheck your race and static sag, and adjust as necessary. When you’re done, get in touch -- we’ll go for a ride…


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