When a sledder talks about adjusting his sag, he’s not referring to the suspenders on his snow pants. “Sag,” a key adjustment on modern long-travel snowmobile suspension, is defined as the distance the suspension settles from its fully extended position when a rider gets on board. When sag is set correctly, you’ll enjoy the best possible ride and employ the full range of suspension travel.
It takes about 100 miles to break in moving parts on a new sled and get the suspension ready for final adjustment. Here’s how to do it yourself.
Step 1. Measure Up
With the fuel tank full and the sled on a flat, firm surface, lift the rear grab handle until the track is off the ground and the suspension is fully extended. Set the machine down and measure the distance between the ground and a reference point on the back of the sled, such as the bottom edge of the grab handle.
Step 2. Settle Down
Board the sled and bounce up and down to settle the suspension. While you’re on the seat, have a friend measure the distance from the ground to the reference point. The difference between the first and second measurement is your sag.
Step 3. Set the Preload
Compare the calculated sag with the spec for your sled, which can be found in the owner’s manual or on a sticker under the hood. If you have too much sag the chassis will bottom out frequently over bumps. To correct this, you need to increase the pre-load tension on the rear suspension springs, usually by using a wrench or a spark-plug socket to rotate a plastic block under each spring end to the next-highest position. On some sleds you’ll need to rotate a collar at the base of the rear coil spring to change its preload.
If you don’t have enough sag, the ride will be stiff and the sled’s center of gravity will be too high. Decrease the spring pre-load by rotating the blocks in the opposite direction.
If you’re extra heavy or extra light, you may not achieve correct sag with the stock springs. In this case, ask your dealer to install an optional spring to suit your weight. The idea is to get the suspension in the middle of its travel with you aboard so you can utilize the full range of motion.