MTB Rear Shock Tips

Hitting a bump in the trail and being pitched up into the air dissipates some of the energy generated from forward motion. Full-suspension mountain bike frames help decrease rider fatigue and maintain momentum by absorbing bumps in the trail. A number of different designs and configurations are available to achieve this, but they need proper setup and maintenance to allow them to function correctly.

  1. Air Shocks

    • Air shocks use a canister of compressed air as a damper for the suspension. This configuration is often seen on high-end cross country race bikes, as an air shock's simple design is extremely light, and geared toward the absorption of small bumps. They are simple to set up, having only one adjustable parameter, air pressure. However, if they are used for extreme or intense runs, the air inside will heat up and expand, altering the compression rate and possibly locking out the shock completely.

    Coil Over Air

    • The most common type of shock is the coil over air variant. A pressurized air shock is supported by a traditional spring on the outside. This essentially gives two compression rates. The coil spring takes the big hits, only engaging the air shock once the spring is compressed. This setup is heavier and requires more trial-and-error to set up correctly, but it gives a "plush" feel to the ride and is capable of handling some serious abuse.

    Setup

    • When setting up a rear shock, it's important to have an accurate reading of your weight. Your weight is used to determine the starting pressure in the shock. Check the manufacturer's manual for a chart converting pressures to rider weights. If the setting is too soft, the suspension with bottom out as soon as you sit on the bike, making the suspension useless and risking damage to the frame. If it is too hard, it won't compress when hitting bumps, effectively giving you a rigid frame. Air shocks are set with a pump, so have one with an accurate pressure gauge to ensure the correct values are being used.

    Maintenance

    • Air shocks are at risk from water, dirt, changes in temperature and sudden impacts. Clean your shock thoroughly after every ride to clear all the mechanisms of mud. Use a bike cleaning spray such as Muc-off, and bounce the suspension repeatedly to push any dirt up and out of the seals. Many riders invest in a snug neoprene sock that covers the shock during use, which can be taken off and thrown in the laundry. Coils are far more hard-wearing, as the tough spring takes most of the hits, so the air portion is fairly unstressed. You should dismantle and clean the internal mechanisms around once a year.