1. Begin by lifting the rear of the machine completely off the ground and loosening the double lock rings until there is no pressure on the spring. At this point, there is no preload on the spring, and ride height is at its lowest possible position. Turning the adjusting ring out three to four complete rotations is a good starting point for a stock rear shock. This puts minimal preload and can typically soften a very stiff shock.
2. The next step is to determine the amount of free sag by measuring the distance from the ground to the grab bar in this raised position and then in its natural-state at-rest position. The difference in the two measurements should equal around 10 percent of the total of shock travel amount. For example, a shock with 10 inches of travel should provide around 1 inch of free sag. To increase the sag, simply reduce the spring tension, and add tension to the spring for less sag. Note: We did this with a single-shock sport model; an IRS model will require you modify the process, using Step 4 with these numbers.
3. Now, repeat this step with the rider (time to enlist a buddy to man the tape measure) on the machine to get the proper race sag. This should equal around one-third of the total shock travel. For the same shock with 10 inches of travel, this would equal 3.33 inches of sag. Race sag is more critical than the free sag, so adjust to achieve correct rider sag, even if this means slightly altering the free sag.
4. Done with the rear shock(s). The next step is to adjust the preload on the front shocks. This is done in the same manner as the rear, by lifting the machine off the ground and loosening the double locking rings. The front shocks must have identical settings for obvious reasons. So loosen the tension on the springs until they are both free-floating, and then count the complete turns of the locking rings when compressing. The goal here is to gain between level and a half inch of rake at the flat point of the frame just behind the rear A-arm mount and the ground over the height of the frame at the pegs. The sweet spot varies with each brand of machine due to a different center of gravity. A good rule to remember is that the more rake or the higher the frame at the front of the machine, the more traction there is at the rear (center of gravity is shifted toward the rear). This also lightens the front end, limiting the machine's ability to slide in turns, so you must determine the height that best suits your machine and riding style.
5. Adjusting the compression is the next step bringing us closer to smooth sailing. The compression adjustment is typically a screw or knob located at the top of the shock or on the nitrogen reservoir (never at the shaft end of the shock). Rotating the screw clockwise adds compression or stiffens the shock and vice versa. You want to adjust the compression to allow full use of the shock travel, while preventing the shock from bottoming. It is inevitable that you will, on occasion, bottom out your shocks, so don't panic; it shows that you are using the full range of travel that the shock provides. However, if bottoming is common, the compression is too soft and needs further adjustment.
6. The ride height is set and compression is adjusted, so now it's time to address the rebound. At the shock's shaft end you will find a collar or screw that controls the speed at which the shock returns to its extended position. This works similarly to the compression screw; clockwise (turn in) speeds up rebound and counterclockwise (turn out) slows rebound. Too fast a rebound makes the shock return out like a pogo-often with a violent punch. Conversely, if the rebound is too slow, the shock won't have adequate time to return, causing the shock to pack up. This is most noticeable in a series of whoops or a rock garden, where multiple impacts occur immediately after one another. Each time the shock compresses, it moves too slowly to fully extend, and the travel becomes shorter and shorter, eventually resulting in no suspension and a thud of kick as it ricochets off the next obstacle. The trick is finding the spot at which it's neither too fast nor slow, but just right. It won't be as easy as Goldilocks finding the perfect bed, but along the same lines. Starting close to the stock position is good, but experiment with two to three clicks at a time to see what works for you.