How to Adjust an MTB Rear Suspension

A full-suspension mountain bike is defined by its reliance on a rear shock to dampen bumps as the rear wheel moves over rough terrain. There are different shocks made by a variety of manufacturers on the market. The two dominant kinds are coil and air shocks. Adjusting these shocks requires a bit of fine-tuning, and even some fractions. A well-tuned rear shock is the key to a fun ride on a full-suspension mountain bike.

Things You'll Need

  • Shock pump
  • Millimeter tape
  • Zip tie
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Instructions

    • 1

      Pump up the shock to its recommended pressure using your shock pump. Make sure to screw the head of the shock pump firmly onto the shock's valve. Inflate to your shock's recommended pressure, which should be included in the instruction manual. If there is no recommended pressure, start by inflating to a psi (pounds per square inch) equal to half your body weight.

    • 2

      Measure the length of the shock's piston with you millimeter tape. The piston is the tube that compresses into the shock body. Many shocks come with a rubber band around the piston to measure the maximum amount of travel on the shock. If your bike does not have this, wrap a zip tie around the piston.

    • 3

      Sit on the bike, then dismount.

    • 4

      Measure the length between the rubber band or zip tie and the shock body. This is the amount of sag on the shock. Divide the movement by the total length of the piston. This is the percentage of sag on the shock. A higher number (between 15 and 25 percent) is optimal for long-travel bikes that ride on more-agressive terrain. A smaller number (between five and 15 percent) is ideal for short-travel bikes that ride fast over smoother terrain. Add or remove air from the shock to decrease or increase sag.

    • 5

      Spin the rebound control knob all the way out so the shock has the maximum amount of movement. Sit on the bike and ride it off a curb. Pay attention to how much it bounces after riding off the curb. Adjust the rebound knob until it bounces only once before it stops moving.