DIY Rear Shock Sag Setup for STX22 Air

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The STX22 Air rear shock by Öhlins is engineered for precision and high performance, offering cyclists a premium experience for aggressive trail riding and competitive mountain biking. One of the most crucial aspects of setting up your rear shock is achieving the correct sag. Proper sag ensures optimal suspension performance by balancing comfort and control. In this guide, we will walk through the steps needed to set up the sag for the Öhlins STX22 Air rear shock, along with maintenance, troubleshooting, and optimization tips to ensure your shock operates at its best.

Tools Required

  • Shock pump (with an accurate gauge)
  • Ruler or tape measure
  • Calibration device (optional)
  • Torque wrench [paid link] (for any bolt adjustments)

Understanding Rear Shock Sag

Before delving into the setup process, it’s essential to understand what sag is and why it’s important. Sag is the amount the shock compresses under the rider’s weight when they’re on the bike. This compression allows the suspension to absorb impacts efficiently, offering a smoother ride and more control, especially on rough terrain.

For the STX22 Air, the recommended sag is typically between 25% to 30% of the shock’s total travel. The exact percentage depends on your riding style, terrain, and rider weight.

Steps for Setting Sag on STX22 Air

Step 1: Prepare the Bike and Rear Shock

  • Make sure your bike is on a level surface, and the rear wheel is properly mounted.
  • Remove any gear or accessories that may affect the weight, such as hydration packs or toolkits.
  • Ensure the rear shock is securely mounted to the frame and the air spring is fully deflated before beginning the setup.

Step 2: Determine Your Rider Weight

Knowing your body weight, including gear and clothing, is critical for accurate sag calculation. This will allow you to adjust the air pressure in the shock accordingly. Add your body weight to any additional gear you plan to carry during rides.

Step 3: Set the Initial Air Pressure

  • Using the shock pump, inflate the STX22 Air shock to an initial pressure based on your rider weight. Refer to Öhlins’ recommended starting points, typically found in the user manual or the manufacturer’s website.
  • As a guideline, you can start with 1 to 2 PSI per kilogram of rider weight. For example, if you weigh 70 kg, the initial pressure should be between 70-140 PSI.

Step 4: Check the Current Sag

  • With the shock inflated, mount the bike and sit on it in a normal riding position.
  • Ensure you’re in a relaxed stance, without any extra pressure placed on the handlebars.
  • Once you’re seated, get off the bike and use a ruler or tape measure to measure the distance between the shock’s eyelet (where the shock connects to the frame) and a fixed point on the frame.
  • Measure the compression of the shock by pressing it down with your weight, then remeasure after getting off the bike.
  • Calculate the sag by comparing the initial measurement to the compressed measurement. The difference between the two measurements represents the amount of sag.

Step 5: Adjust Air Pressure to Achieve Proper Sag

  • If the sag is too little (i.e., the shock isn’t compressing enough), add air to increase pressure.
  • If the sag is too much (i.e., the shock compresses too far), release air to decrease pressure.
  • Adjust the air pressure in small increments (5-10 PSI) until the sag reaches the desired level—25% to 30% of the total shock travel.

Step 6: Fine-Tune Rebound and Compression Damping

  • Once sag is set, move on to adjusting the rebound and compression settings. The STX22 Air shock features multiple damping adjustments that allow you to fine-tune its performance based on terrain.
  • For a more controlled feel, increase rebound damping. For faster response, reduce it.
  • Similarly, adjust the compression damping to suit your riding style and terrain. Higher compression settings are better for aggressive, fast riding, while softer compression suits smoother, technical terrain.

Troubleshooting Common Set-Up Issues

Problem 1: Insufficient Sag (Shock Not Compressing Enough)

  • Solution: This issue often arises from too much air pressure in the shock. Reduce the pressure incrementally and recheck the sag. Ensure that the shock pump’s gauge is accurate for precise readings.

Problem 2: Excessive Sag (Shock Compressing Too Much)

  • Solution: Too little air pressure in the shock can cause the suspension to compress excessively. Inflate the shock and check the sag again. If sag is still too much, gradually add pressure until you reach the desired level.

Problem 3: Inconsistent Performance After Adjusting Sag

  • Solution: If you notice inconsistent performance or a feeling of excessive squishiness, the air pressure may not be properly balanced. Revisit the air pressure adjustments and consider fine-tuning the rebound and compression damping settings. Inconsistent performance can also be a sign of worn seals or internal damage in the shock.

Customization and Optimization for Better Performance

To optimize the performance of your STX22 Air rear shock, consider the following customization tips:

  • Adjust Air Volume: The STX22 Air features an adjustable air volume spacer. By adding or removing spacers, you can customize the shock’s progression. This can help make the suspension more linear or progressive, depending on your preference and riding style.
  • Change Damping Settings Based on Terrain: For trail riding, you may want to set higher compression damping to control the shock on aggressive descents. For cross-country riding, lower compression damping can provide better efficiency on smoother trails.
  • Use a Volume Reducer: If you prefer a firmer, more controlled feel, adding a volume reducer to the air chamber can decrease the shock’s overall air spring volume, giving the rear end a more progressive feel.

Compatibility with Other Drivetrain Components

The Öhlins STX22 Air rear shock is compatible with most modern mountain bike frames that use an eyelet mount system. However, it is essential to check the exact specifications of your bike frame and the shock’s stroke length and mounting hardware to ensure proper fitment.

The shock can be paired with a variety of rear suspension designs, but always ensure that your bike’s rear triangle has the necessary clearance for the STX22 Air’s design and stroke.

Conclusion

Setting up the rear shock sag for the STX22 Air is a crucial step in optimizing your suspension for comfort and performance. By following these detailed steps, adjusting air pressure, and fine-tuning damping settings, you can ensure that your shock operates at peak efficiency. Regular maintenance and understanding the common issues that arise during setup will keep your ride smooth and enjoyable. Whether you’re an experienced rider or just getting started, the Öhlins STX22 Air offers exceptional adjustability to match your riding style and terrain.