How to Rebuild Your STX22 Air Rear Shock at Home

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The Öhlins STX22 Air rear shock is a highly regarded component for its performance and adjustability. Whether you’re looking to rebuild it for maintenance or due to performance issues, rebuilding the STX22 Air is a straightforward process with the right tools and attention to detail. In this guide, we will walk you through the steps involved in rebuilding your STX22 Air rear shock, covering everything from disassembly and cleaning to reassembly and tuning.

Tools Required

  • 8mm hex wrench
  • 10mm socket wrench
  • 17mm spanner
  • Torque wrench [paid link]
  • Shock pump (for air pressure adjustments)
  • Small flat-head screwdriver
  • Cleaning brushes
  • Isopropyl alcohol
  • Rags or microfiber cloths
  • Öhlins STX22 Air rebuild kit (o-rings, seals, and grease)

Disassembly of the STX22 Air Rear Shock

Step 1: Remove the Shock from the Bike

Before beginning the rebuild process, ensure the rear shock is removed from the bike. This will involve:

  1. Use a 5mm hex wrench to remove the bolts securing the shock to the frame.
  2. Carefully slide the shock out of the mount, being mindful of any protective covers or bushings.

Step 2: Remove the Air Sleeve

  1. Use a 10mm socket wrench to remove the air valve from the shock body.
  2. Carefully remove the air sleeve by loosening the 17mm spanner on the top cap of the air chamber.
  3. Once the top cap is removed, slide the air sleeve off the shock body. Make sure you take note of the direction of the seals and the order of components for easier reassembly.

Step 3: Drain the Shock Fluid

  1. With the air sleeve removed, position the shock with the piston side facing downward.
  2. Drain any remaining oil from the shock by gently tapping the body to encourage fluid flow.
  3. Use a rag to clean any excess fluid from the shock body.

Step 4: Remove the Piston Assembly

  1. Using your 8mm hex wrench, carefully unscrew the piston nut that holds the piston assembly in place.
  2. Gently pull out the piston rod and the internal components from the shock body.
  3. Take careful note of how each component is stacked for reassembly.

Cleaning and Inspection

Step 5: Clean All Components

  1. Use a small flat-head screwdriver to remove any old seals or o-rings from the shock body and piston assembly.
  2. Thoroughly clean all parts with isopropyl alcohol and a microfiber cloth, ensuring that there is no dirt or debris.
  3. Inspect each component for any signs of wear, including the air sleeve, seals, piston, and the shock body itself. Replace any worn-out parts with fresh components from your Öhlins rebuild kit.

Step 6: Inspect and Clean the Air Chamber

The air chamber is crucial for the performance of your shock. Ensure that it is clean and free of oil or dirt.

  1. Inspect the air valve and the air sleeve for any signs of damage or leaks.
  2. Wipe down the inside of the air chamber with a clean cloth to ensure it’s free from dirt and grime.
  3. Ensure that the air valve functions smoothly, and replace any worn-out seals or gaskets.

Reassembly of the STX22 Air Rear Shock

Step 7: Install New Seals and O-Rings

  1. Install new seals and o-rings on the piston rod, using the components provided in the Öhlins STX22 Air rebuild kit.
  2. Lubricate the seals with some fresh shock oil to prevent damage during reassembly.

Step 8: Reinstall the Piston Assembly

  1. Insert the piston assembly back into the shock body, ensuring that it is aligned correctly.
  2. Tighten the piston nut securely with an 8mm hex wrench. Be sure to follow the manufacturer’s torque specifications to avoid damaging the piston assembly.

Step 9: Reinstall the Air Sleeve

  1. Slide the air sleeve back onto the shock body.
  2. Reinstall the top cap using the 17mm spanner, securing it tightly.
  3. Reinstall the air valve, making sure it is fully seated to prevent air leaks.

Step 10: Refill with Shock Oil

  1. Fill the shock body with the recommended oil, following the specifications from the Öhlins manual.
  2. Ensure the shock oil level is correct, using a syringe or oil bottle to fill the shock precisely.

Air Pressure and Tuning

Step 11: Set the Correct Air Pressure

  1. Attach a shock pump to the air valve and set the recommended air pressure for your rider weight and riding style.
  2. Ensure the shock is set to the correct pressure by using the shock pump’s gauge.
  3. Double-check the air valve’s sealing by applying a small amount of soapy water to the valve. If bubbles form, replace the air valve seal.

Step 12: Tune the Shock

  1. Adjust the rebound and compression settings according to your preference and the terrain you ride on.
  2. Use a torque wrench [paid link] to ensure all adjustment knobs are set within the recommended torque range to avoid stripping or damaging the shock components.

Troubleshooting Common Issues

Air Leaks

If you notice a loss of air pressure over time, it could indicate an air leak in the shock. Common causes include:

  • Worn-out air valve seals.
  • Incorrectly installed air sleeve.
  • Damaged shock seals.

Inspect all seals and replace them as necessary. If the air valve is the issue, replacing the valve or its seals is often the most effective solution.

Poor Rebound Performance

If your shock feels slow or unresponsive when rebounding, it may be due to incorrect oil levels, worn-out seals, or improper damping settings. Check the oil level and ensure it is filled to the correct level. Adjust the rebound knob and ensure all seals are in good condition.

Insufficient Compression

If your shock is not providing sufficient compression damping, check for air in the system or inadequate oil fill. Refill the oil to the recommended level and check for any air trapped inside the chamber. Additionally, check the compression adjustment knob to ensure it is set properly.

Customization and Optimization

Adjusting for Different Terrain

The STX22 Air rear shock can be tuned to suit different types of riding conditions. For smoother terrain, you might prefer a more plush feel, while a firmer setup may be ideal for aggressive riding and technical trails. Adjusting the air pressure, compression, and rebound damping will help you dial in the perfect setup.

Compatibility with Other Drivetrain Components

The STX22 Air rear shock is compatible with a wide range of bikes and drivetrain systems. However, it’s essential to ensure that the shock’s dimensions are compatible with your bike’s frame and suspension system. Check your bike’s specifications to confirm compatibility, particularly regarding mounting hardware and shock stroke length.

Conclusion

Rebuilding your Öhlins STX22 Air rear shock at home is a manageable task when following the correct procedures and using the right tools. By maintaining the shock, replacing worn-out parts, and fine-tuning its settings, you can significantly improve your bike’s performance and extend the lifespan of the shock. Regular maintenance will keep your rear shock performing at its best, ensuring a smoother and more controlled ride on all types of terrain.