Sag – it may only be a three letter word, but it plays a huge role in how your full suspension bike rides. When you sit on your bike, your rear shock will sink a certain amount into it’s travel – this is referred to as sag. The amount of recommended sag will vary depending on the type of bike that you ride. Typically, enduro/trail bikes fall between 25% – 35% recommended sag, while downhill bikes can be up to 40% recommended sag. At the other end of the spectrum, short travel cross country bikes are going to be closer to 20% – 30% recommended sag. These numbers are just guidelines though, and may vary depending on suspension kinematics, leverage ratios, and other factors. With the exception of downhill bikes, most other full suspension bikes are running air shocks these days. And many of these air shocks have laser-etched guides showing exactly where you sit in your travel, which takes the guesswork out of the sag calculation. Simply sit on the bike with your geared-up weight, and see where your sag ring ends up. Be sure not to bounce up and down, as this will not provide an accurate sag measurement. You can then adjust your air pressure up or down to hit your exact target sag percentage. But what if your rear shock doesn’t have those sag measurements etched? Or what if you’re trying to measure sag on a downhill bike with a coil shock? You can try to eyeball the percentage of sag, and generally that will work okay. But if you’re a perfectionist like us, “pretty close” isn’t good enough. Many of us here at Fanatik are pretty particular about the amount of sag we prefer, depending on which bike it is we’re riding. Calculating sag may seem daunting, but it’s actually pretty easy. I’ve broken it down into four easy steps. You’ll need a ruler or measuring tape with millimeters, a buddy, a calculator, and most likely a shock pump.