Changing the oil in your Fox 34 Performance suspension fork is a vital maintenance procedure that ensures optimal performance and prolongs the life of the fork. Performing this task at home can save money and keep your ride in top shape when done correctly. This guide provides a comprehensive walkthrough of the oil change process specific to the Fox 34 Performance fork, including preparation, step-by-step instructions, common troubleshooting tips, and performance enhancements.
Tools Required
- 10 mm socket wrench
- Torque wrench [paid link] (with Nm scale)
- 2 mm and 5 mm hex keys [paid link]
- Flat-blade screwdriver
- Pick tool or dental pick
- Suspension-specific oil (Fox 20wt Gold or recommended alternative)
- Measuring syringe or graduated cylinder
- Clean rags or paper towels
- Isopropyl alcohol (99% preferred)
- Rubber mallet (optional)
- Nitrile gloves
- Oil drain pan
Understanding the Fox 34 Performance Fork
The Fox 34 Performance is designed for aggressive trail riding and features a FIT GRIP damper. It lacks the Kashima coating seen in Factory models but retains internal quality. Understanding this fork’s layout is crucial for maintenance. It includes a lower leg assembly housing the bath oil and air spring lubrication, which requires regular oil changes to maintain sensitivity and seal longevity.
Recommended Service Interval
Fox recommends lower leg oil servicing every 30 to 50 hours of riding. Delaying this service can result in decreased performance, stiction, and premature seal wear. Riders operating in wet or dusty conditions should adhere to the shorter end of this range.
Pre-Service Preparation
Ensure the fork is completely clean and dry before beginning. Place the bike on a repair stand to keep it stable, and remove the front wheel and brake caliper. It’s also recommended to remove the fork from the frame for easier handling during the oil change process.
Draining the Old Oil
Begin by removing the air from the fork using the Schrader valve at the top of the left leg. Press the valve gently until all pressure is released. Then, use a 5 mm hex key to remove the air side bottom bolt and a 2 mm hex key to unthread the rebound adjuster before removing the damper side bolt. A rubber mallet can help break the seal between the lower legs and the upper tubes. Once loosened, carefully slide off the lower legs and invert them to drain the old oil into the pan.
Cleaning Internal Components
Thoroughly clean the inside of the lower legs using isopropyl alcohol and a lint-free cloth. Use a pick tool to inspect and gently clean around the dust wipers and foam rings. Check the foam rings for saturation and replace or re-soak them in fresh suspension oil as needed. Inspect all seals for damage and replace them if wear is evident.
Refilling with Fresh Oil
Use a syringe or graduated container to measure the correct oil volume. For the Fox 34 Performance, typically 40 cc of 20wt Gold oil goes into each lower leg. Pour oil into the fork leg channels carefully, avoiding spillage into unintended areas. Reinstall the lower legs onto the stanchions evenly and slowly to prevent air entrapment.
Reassembly and Torque Specifications
Reinstall the bottom bolts: torque the air side bolt to 5.1 Nm and the damper side to 7.3 Nm. Reinsert the rebound knob securely using the 2 mm hex key. Inflate the air spring back to the desired pressure and verify that all bolts are torqued correctly. Finally, reinstall the fork on the frame, the brake caliper, and the front wheel.
Post-Service Inspection
Cycle the fork through its travel a few times to evenly distribute the oil. Check for smooth operation, unusual noises, or leaks. A short test ride can help ensure everything feels correct and no air was trapped during reassembly.
Troubleshooting Common Issues
Some users may encounter leaks shortly after a service. This usually results from damaged seals or improperly torqued bolts. Double-check all seals for seating and inspect the foam rings. If the fork feels sticky, verify that the oil volume was correct and that the dust wipers are properly lubricated.
If compression or rebound feels inconsistent, recheck the rebound knob installation and the damper bolt torque. Air pressure leaks often point to a faulty Schrader valve or an issue with the air-side seal head.
Performance Optimization Tips
To enhance the performance of your Fox 34 Performance fork:
- Upgrade the stock foam rings to larger capacity aftermarket options to improve lubrication retention.
- Use high-quality synthetic suspension oils designed for consistent viscosity across temperature ranges.
- Consider adding volume spacers to tune bottom-out resistance according to rider weight and terrain.
Adjusting the air pressure and rebound according to rider weight and trail conditions ensures the best responsiveness. Routinely check and match the air pressure to your settings post-service.
Compatibility With Other Components
The Fox 34 Performance fork is designed to work seamlessly with modern trail and all-mountain setups. It is compatible with both 29″ and 27.5″ wheels, depending on the model version. Ensure that the axle standard (Boost 110 mm vs. non-Boost 100 mm) matches your hub configuration.
The fork is best paired with Fox or Shimano drivetrains for cohesive performance. Brake compatibility should also be verified, as the fork uses a post-mount system that supports up to 180 mm rotors natively.
Comparing the Fox 34 Performance With Other Forks
Compared to the Fox 34 Factory, the Performance model forgoes the Kashima coating but maintains similar internals. The Performance Elite variant adds a FIT4 damper for better high-speed adjustment.
In contrast to the RockShox Pike Select, the 34 Performance offers comparable stiffness and weight but may feel slightly less plush due to the GRIP damper. For riders prioritizing ease of maintenance and proven trail performance, the 34 Performance remains a cost-effective and reliable option.
FAQs
How often should I change the oil in my Fox 34 Performance fork?
Every 30 to 50 hours of riding is recommended, or sooner in harsh conditions.
Can I use a different oil than Fox 20wt Gold?
Only use Fox-approved alternatives with matching viscosity and additive profiles.
Do I need to remove the fork from the bike to change the oil?
It’s not mandatory, but removing the fork can simplify the process and improve access.
Why is my fork leaking oil after a service?
This often indicates improper seal seating or excess oil. Recheck seals and oil volume.
Can I upgrade my Fox 34 Performance damper to a FIT4?
Yes, but it requires purchasing a compatible damper assembly and professional installation.
Is the 34 Performance suitable for enduro riding?
It handles moderate enduro terrain but may not match the stiffness or travel range of the 36 series.
Conclusion
Changing the oil in your Fox 34 Performance fork is a manageable DIY task that keeps your suspension working smoothly. Regular servicing not only enhances ride quality but also extends the lifespan of your investment. Following the correct procedures and using quality tools ensures a professional-grade result, even from your home workshop.