The TTX22M Trunnion [paid link] rear shock from Öhlins is a high-performance component designed to offer superior shock absorption and adjustability for road bikes. Over time, it may require maintenance or rebuilding to keep it performing at its best. This guide will take you through the step-by-step process of rebuilding the TTX22M Trunnion [paid link] rear shock at home. Whether you’re looking to restore its performance or ensure its longevity, this detailed, technical guide covers all aspects of the rebuild process.

Tools Required

• 10mm and 12mm socket wrenches
• T25 Torx driver
• Shock pump
• Oil drain pan
• Clean lint-free rags
• Silicone grease
• Replacement seals and oil (specific to TTX22M Trunnion)
• Needle nose pliers
• Snap ring pliers
• Torque wrench [paid link]
• 3mm and 4mm hex wrenches
• Soft mallet or hammer (with protective head)
• Plastic pry tools

Preparation for Rebuilding the TTX22M Trunnion Rear Shock

Before beginning the rebuild, ensure that you have a clean, well-lit workspace where you can comfortably disassemble and work on the rear shock. Having all the necessary tools and replacement parts at hand will streamline the process and minimize any delays. Additionally, wearing gloves is recommended to keep the shock clean and free of contaminants.

Removing the Shock from the Bike

1. Release the Rear Shock from the Frame:
   • Use a 10mm socket wrench to remove the mounting bolts securing the shock to the bike frame. Carefully slide the shock out of the frame, making sure not to damage any components in the process.
2. Remove the Trunnion Mounts:
   • Use the appropriate tool (often a 12mm socket wrench) to detach the trunnion mounts from both sides of the shock. If the mounts are stuck, gently tap them with a soft mallet to loosen them.
3. Inspect the Shock:
   • Before proceeding with the rebuild, inspect the shock for any obvious damage or wear. Check the trunnion mount area for cracks or bending and ensure there are no external oil leaks.

Disassembling the TTX22M Trunnion Rear Shock

Draining the Oil

1. Place the Shock in an Oil Drain Pan:
   • Position the shock upside down in an oil drain pan to allow any remaining oil to drain. Make sure the area around the shock is clean to avoid contamination.
2. Remove the Air Valve:
   • Use a T25 Torx driver to carefully unscrew the air valve. This step is crucial to release any pressure in the shock, ensuring safe disassembly.
3. Drain Remaining Oil:
   • Once the air valve is removed, let the shock sit for a few minutes to allow any residual oil to drain completely. The oil used in the TTX22M Trunnion is specific to the model, so ensure you dispose of it properly.

Removing the Outer Casing

1. Loosen the Shock Housing:
   • Use a 4mm hex wrench to loosen the screws securing the outer casing of the shock. Carefully remove the casing, ensuring you do not damage the internal components or seals during the process.
2. Extract the Piston Assembly:
   • Using your hands or a set of needle nose pliers, gently remove the piston assembly from inside the shock body. Be cautious during this step, as the piston assembly is delicate and can be easily damaged if forced.
3. Remove the Internal Damper:
   • Use a soft mallet or a hammer with a protective head to gently tap the internal damper out of the shock body. Take care not to bend or damage the damper during removal.

Removing and Replacing Seals

1. Pry the Old Seals Off:
   • Using a plastic pry tool, carefully remove the old seals from the shock body. Ensure the pry tool is clean to prevent contamination from entering the shock.
2. Clean the Shock Body:
   • Before installing new seals, thoroughly clean the shock body using a lint-free rag. Ensure no oil or dirt remains in the shock to prevent contamination when you install the new seals.
3. Install the New Seals:
   • Apply a thin layer of silicone grease to the new seals and carefully install them into their designated slots. Ensure they sit properly to avoid any leakage once the shock is reassembled.

Reassembling the TTX22M Trunnion Rear Shock

Installing the Internal Damper

1. Insert the Internal Damper:
   • Place the internal damper back into the shock body. Align it properly and gently tap it into place using a soft mallet. Be cautious not to force the damper as this could lead to damage.
2. Attach the Piston Assembly:
   • Slide the piston assembly back into the shock body, ensuring it is seated securely. Double-check for any misalignment, as this could affect the performance of the shock once reassembled.

Sealing and Reattaching the Outer Casing

1. Install the Outer Casing:
   • Carefully place the outer casing back onto the shock body. Tighten the screws with a 4mm hex wrench to ensure a secure fit.
2. Reinstall the Air Valve:
   • Use the T25 Torx driver to reinstall the air valve. Ensure it is tightened to the manufacturer’s specifications to avoid any air leaks.
3. Final Seal Check:
   • Before moving to the next step, double-check all seals and casings to ensure they are seated properly and there is no chance of leakage.

Refilling the Shock with Oil

1. Select the Correct Oil:
   • Use the recommended shock oil for the TTX22M Trunnion, ensuring that it meets the correct viscosity and volume requirements for your specific model.
2. Fill the Shock:
   • Slowly pour the oil into the shock body, ensuring that it is filled to the appropriate level. Be careful not to overfill, as this can affect the shock’s performance.
3. Check for Air Bubbles:
   • After filling the shock, tap the shock gently to allow any air bubbles to rise to the surface. This step helps to avoid air pockets that can compromise the shock’s damping performance.

Final Adjustment and Testing

Reattaching the Shock to the Frame

1. Mount the Shock Back to the Frame:
   • Attach the shock back to the frame using the same mounting bolts and trunnion mounts that were removed earlier. Tighten the bolts securely, but be careful not to overtighten as this could damage the threads.
2. Check the Suspension Settings:
   • Set the correct sag and rebound settings based on your riding preferences and weight. Use a shock pump to adjust the air pressure to your desired setting.

Testing the Shock Performance

1. Perform a Full Compression Test:
   • With the shock reassembled and mounted on the bike, perform a full compression test by pressing down on the bike’s rear end. Ensure the shock compresses and rebounds smoothly without any unusual resistance or sounds.
2. Test Ride the Bike:
   • Take the bike for a test ride, paying attention to any performance issues such as improper damping, excessive noise, or sluggish rebound. If necessary, make further adjustments to the air pressure or rebound settings.

Troubleshooting Common Set-Up Issues

Air Leaks

• Problem: If you notice a loss of air pressure, there may be a seal issue or an improperly tightened air valve.
• Solution: Check the air valve and seals for proper installation and ensure that they are tight and free of any dirt or damage.

Damping Issues

• Problem: If the shock feels too soft or too stiff, it could be due to incorrect oil levels or a malfunctioning damper.
• Solution: Recheck the oil level and ensure that the damper is properly assembled. If the issue persists, the damper may need to be replaced.

Noisy Shock

• Problem: If the shock is making unusual sounds such as squeaking or grinding, it could be due to a lack of lubrication or a damaged seal.
• Solution: Check the seals and apply a thin layer of silicone grease to reduce friction and noise. If the problem continues, inspect for damage.

Conclusion

Rebuilding the Öhlins TTX22M Trunnion rear shock at home is a highly rewarding task for riders looking to maintain their suspension system’s performance. By following this step-by-step guide, you can ensure that your shock performs optimally and is ready for any riding conditions. Regular maintenance and proper care will extend the life of your shock and enhance your riding experience.