The Fox DHX Trail rear shock is designed for demanding trail riding, offering a durable and versatile suspension solution for various mountain bikes. Regular maintenance ensures the longevity and optimal performance of your shock, making it crucial to follow a structured approach to servicing. This guide will take you through the essential steps to maintain, troubleshoot, and optimize your DHX Trail rear shock, ensuring peak performance for every ride.

Tools Required

• Fox-specific shock pump
• 5mm and 6mm Allen wrenches [paid link]
• 8mm spanner wrench
• Torque wrench [paid link] (5-30 Nm)
• T20 and T25 Torx drivers
• Clean rags
• Suspension fluid (Fox Float Fluid)
• O-ring grease
• Sealant (if necessary)
• Dropper post tool (for removing shock if integrated with a dropper post)

Removing the Shock for Servicing

Before beginning any servicing work, it’s essential to safely remove the shock from the bike.

1. Lift the bike and secure it: Use a bike stand [paid link] or stable platform to raise the bike, ensuring that the rear suspension is fully extended.
2. Loosen the mounting bolts: Use a 5mm Allen wrench [paid link] to remove the bolts holding the shock to the frame at both ends.
3. Remove the shock: Carefully remove the shock from the frame. If your shock is integrated with a dropper post, use a dropper post tool to release it safely.

Disassembling the DHX Trail Rear Shock

Once the shock is removed from the bike, disassembly is required for thorough cleaning and servicing.

1. Remove the air can: Begin by using the correct Fox-specific shock pump to release all air from the shock. Then, remove the air canister by loosening the bolts securing it to the shock body.
2. Inspect the air can seals: Once removed, inspect the seals for any wear or damage. If the seals are compromised, replace them to prevent air leakage.
3. Disassemble the damper: Using T20 or T25 Torx drivers, carefully remove the damper assembly. Keep all components organized to avoid any confusion during reassembly.
4. Check for fluid leakage: Inspect all components for signs of fluid leakage. Leaking fluid indicates worn seals that need to be replaced.

Cleaning and Lubing the DHX Trail Rear Shock

Maintaining cleanliness in your shock assembly is vital for long-term durability.

1. Clean the shock body: Use a clean rag to wipe down the shock body and any components that come into contact with dirt or debris. Avoid using harsh chemicals as they can damage the shock’s finish.
2. Clean the air can: Wash the air can thoroughly with water and mild soap, ensuring that no contaminants remain inside the chamber.
3. Re-lube the seals: Apply a small amount of O-ring grease to the seals before reassembling the shock. This will help maintain the seal integrity and prevent dirt from entering the shock body.

Reassembling the DHX Trail Rear Shock

Reassembling your shock correctly is crucial to ensuring it functions properly after servicing.

1. Reinstall the damper: Carefully reinstall the damper assembly back into the shock body, ensuring that all components are seated correctly.
2. Replace seals if necessary: If any seals were found to be worn or damaged, replace them before reassembling the shock. This step is critical to maintaining proper shock pressure.
3. Attach the air can: Reattach the air can to the shock body, ensuring it is aligned properly. Tighten the bolts using a torque wrench [paid link] to the specified torque (typically 8-10 Nm).
4. Recheck for leaks: Once reassembled, check for any fluid leakage around the seals or air can. If any leakage is detected, disassemble the shock and recheck the seal installation.

Reinstalling the Shock on the Bike

After servicing, it’s time to reinstall the shock and set it up for optimal performance.

1. Position the shock: Carefully align the shock with its mounting points on the frame and the rear triangle.
2. Tighten the mounting bolts: Secure the shock by tightening the mounting bolts using a 5mm Allen wrench [paid link]. Use a torque wrench to tighten them to the manufacturer’s recommended torque setting (typically 5-6 Nm).
3. Check the suspension for proper movement: Once the shock is installed, check that the rear suspension moves smoothly without any resistance or unusual noises.

Setting the Air Pressure

Proper air pressure is essential for maintaining optimal performance. Setting the correct pressure ensures that the shock provides the right amount of support for your weight and riding style.

1. Use a Fox shock pump: Attach a Fox-specific shock pump to the air valve and pressurize the shock to the recommended pressure based on your weight. For most riders, a general guideline is 250-300 PSI, but this varies based on rider weight and preference.
2. Check the sag: After setting the pressure, sit on your bike and check the sag. Aim for around 25-30% of travel when you’re in your riding position. Adjust the air pressure as needed to fine-tune the sag.

Troubleshooting Common Issues

The Fox DHX Trail rear shock is a highly reliable piece of equipment, but like all components, it can experience issues over time. Here are common problems and troubleshooting steps:

1. Shock Not Holding Air

If your shock loses air pressure, the seals may be damaged. Inspect the seals around the air can and damper assembly for visible wear or cracks. Replacing the seals is usually the solution.

2. Unresponsive Suspension

If the suspension feels too stiff or unresponsive, it may be due to improper air pressure or an issue with the damper. Double-check your air pressure settings, and if the problem persists, consider servicing the damper internals.

3. Fluid Leaks

Fluid leaks are often a sign of damaged seals. If you notice any suspension fluid leaking from the shock body, inspect the seals and replace them immediately. If the leak is more severe, the damper assembly may need to be fully serviced or replaced.

Customizing the DHX Trail Rear Shock

The DHX Trail shock offers several ways to customize your ride, including:

1. Adjusting the Compression and Rebound: Fine-tune the shock’s performance to suit your riding style by adjusting the compression and rebound settings. This can help provide more control on technical terrain and improve comfort on longer rides.
2. Changing the Air Pressure: The air pressure in your shock determines how stiff or soft it feels. By adjusting the pressure, you can fine-tune the shock’s responsiveness to your weight and riding conditions.

Optimizing Performance for Trail Riding

To maximize the DHX Trail’s performance, consider the following adjustments:

1. Fine-Tune the Rebound: The rebound adjustment controls the speed at which the shock returns to its original position after compression. On technical terrain, a slower rebound setting can offer more control, while a faster rebound setting works better on smoother trails.
2. Adjust the Compression: The compression setting affects how the shock absorbs impacts. On steep or rocky trails, a firmer compression setting helps reduce bottoming out, while a softer setting is ideal for smoother trails.

Compatibility with Other Drivetrain Components

The DHX Trail rear shock is compatible with most mountain bike frames that feature a standard shock mount. However, when pairing with different drivetrains, it’s essential to ensure that the frame geometry and shock specs are compatible with your bike’s setup. Always consult your bike frame manufacturer’s specifications to ensure compatibility and optimal performance.

Conclusion

Proper maintenance and care of your Fox DHX Trail rear shock will ensure that it remains a high-performing suspension system for your mountain bike. Regular servicing, proper air pressure, and careful attention to seals and fluid levels are essential to prolonging the life of the shock and maintaining its responsiveness on challenging trails. By following this guide, you can optimize the performance of your shock, address common issues, and ensure that your bike is always ready for the next adventure.