Measuring & Setting Sag

To achieve the best performance from your Fox suspension product, the proper measuring and setting of sag is vitally important. As a starting point, set sag for your fork or rear shock to 25% of active travel.

Note:   While 25% sag is more than adequate for most riders, you can experiment and vary your sag percentage some to better suit your riding style, or personal preferences of handling characteristics and feel. For example, if your style is more downhill/shuttle, you can increase your sag percentage a few points (which implies less air pressure) to add some plushness to your riding platform. If your style is more all-mountain/XC, you can decrease your sag percentage a few points (which implies more air pressure), to firm up your suspension platform.

  1. Fox suspension products typically have an o-ring on the shock body or fork upper tube, but if there is no o-ring, you can use a zip tie. Before mounting your bike, slide the o-ring or zip tie against the scraper lip of the air sleeve, or the scraper lip of the fork dust seal. Be sure to turn off Propedal or lockout on the shock or fork, as applicable.
  2. Dressed to ride (including filled hydration bag, if you use one), position your bike next to a wall or table to support yourself. Without bouncing, mount your bicycle. Assume a normal riding position for at least 30 seconds, to let the suspension fully settle. Distribute your weight evenly between the saddle, handlebars and pedals, as you would naturally position yourself when riding. The o-ring or zip tie will be moved to the equilibrium point on the body or upper tube, as the suspension settles under your weight.
  3. The next step is critical for getting an accurate sag measurement. Dismount your bike without bouncing or pushing downward, without further displacing the o-ring or zip tie.
  4. Measure the distance between the scraper lip and the o-ring or zip tie, and divide that by the total active travel of your shock or fork. For example, if your target sag percentage is 25% and your rear shock active travel is two inches (~50 mm), your target sag setting will be ½ inch (~12.5 mm), which is 25% of active travel (12.5 ÷ 50 = 0.25). Add or release air in 5 PSI (0.35 bar) increments with the FOX Racing Shox HP pump, and repeat steps one through four until your measured sag equals 25% of total active travel.

    Note:  With TALAS forks, always set sag at the highest TALAS travel setting.

  5. If your bike is fully suspended, make sure your sag percentage setting is equivalent for the fork and rear shock.