The RockShox Deluxe Ultimate RCT rear shock is a high-performance suspension component designed for riders who demand precision and comfort on technical trails. Regular maintenance, including oil changes, is essential to keep the shock working at its peak. Over time, the shock’s internal oil can degrade, leading to reduced performance. This guide will walk you through the process of changing the oil in the Deluxe Ultimate RCT, ensuring your shock stays in top condition for optimal performance.

Tools Required

• RockShox rear shock pump
• 5mm and 8mm Allen wrenches [paid link]
• Torque wrench [paid link]
• 10mm socket wrench
• 10mm open-end wrench
• Shock fluid (RockShox suspension oil recommended)
• Small container for oil catch
• Clean rags or paper towels
• A clean workbench or surface for disassembly
• Plastic gloves for cleanliness
• Small syringe or oil transfer tool
• RockShox sealant grease

Disassembling the Deluxe Ultimate RCT Rear Shock

Before beginning any maintenance, ensure that you have properly dismounted the shock from the bike frame and secured it in a clean, well-lit workspace. Follow these steps to disassemble the shock:

1. Remove the Shock from the Bike
   Use a 5mm Allen wrench [paid link] to remove the bolts securing the rear shock to the bike frame. Be cautious not to lose the bolts and washers during removal. Set them aside in a safe place.
2. Prepare the Shock for Oil Change
   Place the shock on a clean surface and ensure that it is upright. This will help prevent oil spillage when you remove the air canister later.
3. Remove the Air Canister
   Using the 8mm Allen wrench [paid link], remove the air canister from the shock body. This is done by unscrewing the canister bolt that holds it in place. Be careful when removing the air can, as some oil may be released during this step.

Draining Old Oil

Now that the shock is disassembled, the next step is to drain the old oil:

1. Position the Shock for Oil Drainage
   Place the shock over a small container or a rag to catch any remaining oil when the shock body is turned. Ensure you have adequate surface protection, as the oil can be messy.
2. Remove the Oil Damper Cartridge
   Using the 10mm socket wrench, unscrew the top nut that holds the oil damper cartridge in place. After removing the nut, pull the cartridge out gently. You should notice some oil draining out during this process. Be prepared to catch the oil with your container.
3. Drain Remaining Oil
   Once the damper cartridge is removed, tilt the shock body to drain the remaining oil from the system. Allow the shock to sit for a few minutes to ensure that all the old oil has been drained.

Cleaning the Shock Components

Before installing the new oil, you must clean the shock’s internals to prevent any contamination:

1. Clean the Damper Cartridge
   Wipe down the oil damper cartridge with a clean rag or paper towel. Ensure that all debris and oil residue are removed.
2. Clean the Shock Body
   Use a clean rag to wipe down the shock body. Inspect the inner tube for any signs of wear or damage. If you notice any damage, consider contacting RockShox for further assistance before continuing.
3. Lubricate O-Rings and Seals
   Apply a thin layer of RockShox sealant grease to the O-rings and seals inside the shock. This helps maintain their effectiveness and ensures a smooth reassembly process.

Installing New Oil

With the shock components clean and ready, you can now proceed with the installation of fresh oil:

1. Fill the Damper Cartridge with New Oil
   Using a syringe or oil transfer tool, fill the damper cartridge with new suspension fluid. Be sure to use the recommended RockShox suspension oil for optimal performance. Fill the cartridge until it is about 80% full, ensuring you leave enough space for air compression.
2. Insert the Damper Cartridge
   Once the damper is filled with oil, carefully slide it back into the shock body. Secure it by tightening the top nut using your 10mm socket wrench. Make sure it is torqued to the manufacturer’s specifications for proper sealing.
3. Reassemble the Air Canister
   Reattach the air canister to the shock body by aligning it properly and screwing it in place with your 8mm Allen wrench. Ensure the canister is torqued to the manufacturer’s specifications.

Reassembling the Shock and Checking for Leaks

Now that the shock has fresh oil, you can begin the reassembly process:

1. Reconnect the Shock to the Bike
   Position the shock back onto the frame and reattach it using the 5mm Allen wrench. Ensure the bolts are tightened to the manufacturer’s torque specifications.
2. Check for Leaks
   Once the shock is back in place, check for any oil leaks around the seals or air canister. If you notice any leaks, tighten the bolts and recheck. If the leaks persist, disassemble the shock and inspect the seals for damage.

Final Adjustments and Testing

After reassembling the shock, perform the final checks:

1. Set the Correct Air Pressure
   Use a RockShox rear shock pump to adjust the air pressure in the shock to the recommended settings for your rider weight and riding style.
2. Test the Shock
   With the shock mounted back on the bike, test the rear suspension by compressing it and checking for smooth movement. Pay attention to any unusual sounds or resistance that could indicate improper oil levels or a problem with the assembly.
3. Perform a Test Ride
   Take the bike for a test ride to ensure that the shock is functioning correctly. Pay attention to comfort, responsiveness, and any signs of oil leakage. If everything feels normal, the oil change is complete.

Troubleshooting Common Issues

If you encounter issues during or after the oil change, here are some common problems and their solutions:

1. Shock Is Not Rebounding Properly
   This could be due to air pressure issues or insufficient oil levels. Check the air pressure and ensure the oil level is correct.
2. Leakage Around Seals
   If oil is leaking from the seals, it may indicate that the seals were not properly lubricated during reassembly or they may be worn out. Re-grease or replace the seals as necessary.
3. Unusual Sounds or Resistance
   Unusual sounds or resistance could be a sign of contamination or air trapped inside the shock. Recheck the oil change process and ensure everything was installed correctly. Perform a bleed if necessary.

Conclusion

Regular oil changes for your RockShox Deluxe Ultimate RCT rear shock are essential to maintain its performance and longevity. By following this detailed, step-by-step guide, you can ensure your shock operates smoothly, providing a comfortable and responsive ride.