Are you an avid recreational mountain biker? Have you ever adjusted your shock pressure? Odds are, you haven’t. When you get a bike tune-up, most shops do it for you, but they base it solely off your bodyweight. That’s a good start, but to get the best ride out of your bike, you have to fine-tune it—and there’s no better tool to do so than the RockShox High-Pressure Digital Fork/Shock Pump. This durable, metal-component pump reads pressure to the tenth of a PSI, all the way up to 300.
To fine-tune your suspension, the first step is to set your “sag,” which is the proportion of shock travel that compresses under bodyweight alone. Optimal sag is 20-30%, which is typically the difference of a couple of PSI—that’s why a precise, digital pump is critical. While some front forks and rear air-shocks are stamped with sag measurements, most aren’t. If that’s the case, you can use calipers to measure the fork or shock’s full travel and then calculate sag as a proportion of that measurement.
To start, pressurize your shock based on your weight (look up a table for your specific shock online). This is where most bike shops stop after a basic tune-up—but you know better now! Then, using calipers and the rubber gaskets on your shocks (or a plastic zip-tie strapped around a stanchion), measure how much the shock compresses when you sit on the bike. Get off the bike, and using the pump, add or remove pressure to 20%, 25%, and 30% sag, making note of how many PSI it takes to hit each one. 20% is a standard starting point, but knowing the measurements for the others allows you to quickly adjust on the trails to see what you like (the shock pump easily fits in a hip-pack). A lower sag has more bump sensitivity and a smoother ride, while a higher sag has a firmer, more efficient ride—something often preferred by enduro riders with shorter travels. Fortunately, adding or removing small amounts of air is easy with the smooth pump arm and precise air-release mechanism on the RockShox pump.
For a basic rear air-shock, the job is done. For a front fork, however, you’ll also need to adjust the rebound. Refer to this page to determine the ideal rebound adjustment for your RockShox fork.
With the Digital Fork/Shock Pump in hand, it’s time to hit the trails knowing that you’re getting the most out of your mountain bike. Experiment on the town trails first, then send some big loops in the Gallatin foothills with the smoothest-riding bike you’ve likely had in a long time.
Find a local dealer at sram.com; $82.