Step-by-Step: Rebuilding Your DH38 Race Suspension Fork

The DH38 Race [paid link] suspension fork from Öhlins is a high-performance component designed for downhill riders seeking maximum control and precision. Over time, maintaining and rebuilding the fork is crucial to ensure it continues to perform at its best. In this guide, we’ll walk you through the step-by-step process of rebuilding your DH38 Race [paid link] suspension fork. We’ll cover everything from installation and adjustments to maintenance, troubleshooting, and optimization for better performance.

Tools Required

5mm Allen key
6mm Allen key
8mm Allen key
10mm Allen key
24mm socket wrench
Torque wrench [paid link] (range 0-40 Nm)
Piston seal driver
Suspension fluid (Öhlins recommended)
Stanchion grease
Cleaning materials (rags, solvent)
Suspension fork service kit (including O-rings, seals, and washers)

Disassembling the DH38 Race Fork

Before you start the rebuild process, make sure to have your tools ready and work in a clean, well-lit area. A bench or stand to secure the fork is essential for better handling.

Step 1: Remove the Fork from the Bike

Begin by loosening the headset bolts using a 5mm Allen key.
Once the bolts are loosened, carefully remove the fork from the frame, making sure to keep the axle, crown, and steerer tube safe.

Step 2: Disassemble the Wheel and Axle

Remove the front wheel from the fork.
For the DH38 Race fork, you’ll need to remove the axle by unscrewing the axle bolts with a 6mm Allen key.
Clean the axle thoroughly with a rag to remove dirt and old grease before continuing with the rebuild.

Step 3: Remove the Lower Leg Assembly

To access the internals, you’ll need to remove the lower legs.
Use a 24mm socket wrench to remove the bolts securing the lower legs to the fork’s stanchions.
Carefully slide the lower legs off the stanchions and set them aside.

Step 4: Drain the Suspension Fluid

Place a clean container under the fork to catch the old suspension fluid.
Unscrew the fluid reservoir cap, typically located on top of the fork leg.
Allow the fluid to drain completely. This will help remove any contaminants that could affect performance.

Step 5: Remove the Internal Components

With the fork legs removed, you can now access the internal components such as the damper and spring assembly.
Use an 8mm Allen key to remove the bolts securing the damper assembly inside the fork.
Gently slide the damper out and inspect it for wear or damage.
For the spring, release the pressure and remove it from the fork leg. Make sure to note the position of any spacers or preload adjusters for reassembly.

Inspecting and Cleaning the Components

Now that the fork is disassembled, it’s time to inspect and clean each part to ensure optimal performance.

Step 6: Clean the Stanchions and Lower Legs

Use a rag soaked in solvent to clean the stanchions thoroughly. Remove all old oil, dirt, and debris.
Similarly, clean the lower legs, checking for any signs of wear or damage to the seals and internal components.

Step 7: Inspect the Seals and O-Rings

Carefully check the fork seals, O-rings, and washers for signs of wear. If any components appear damaged, replace them with the new seals from your suspension fork service kit.
Inspect the damper and air spring components. Any signs of leakage or damage should be addressed by replacing the affected parts.

Rebuilding the DH38 Race Fork

Once the components are cleaned and inspected, you can begin the rebuilding process.

Step 8: Reassemble the Damper and Spring Assembly

Begin by reinstalling the damper into the lower leg. Secure it using the 8mm Allen bolts. Tighten them to the manufacturer’s recommended torque settings (usually around 25-30 Nm).
If your DH38 Race fork uses an air spring, carefully reassemble the air spring unit, ensuring all spacers, washers, and O-rings are properly positioned.
Reinstall the spring into the fork leg, making sure to correctly place any preload adjusters or spacers.

Step 9: Apply Suspension Fluid

Refill the fork legs with the appropriate amount of suspension fluid recommended by Öhlins for the DH38 Race model.
Use a clean funnel to avoid contamination and ensure the fluid level is correct. Most Öhlins forks require approximately 200-250ml of fluid per leg, but always double-check with the manufacturer’s specifications.

Step 10: Reassemble the Lower Legs

Once the suspension fluid is in place, carefully slide the lower legs back onto the stanchions.
Tighten the bolts securing the lower legs to the fork. Again, use a torque wrench [paid link] to ensure you’re applying the correct amount of force, typically between 10-12 Nm.

Step 11: Install the Axle and Wheel

Reinstall the axle and secure it using a 6mm Allen key. Ensure that the axle is properly aligned and tightened to the correct torque setting.
Reinstall the front wheel and ensure that it is properly aligned with the fork and securely tightened.

Adjustments and Fine-Tuning

Now that the DH38 Race fork is reassembled, it’s time to make any necessary adjustments to ensure it performs at its best.

Step 12: Adjust the Rebound and Compression

The DH38 Race fork features adjustable rebound and compression settings. Start by setting the rebound to a mid-range position and adjust the compression to your desired firmness based on riding style.
Use the rebound and compression dials to make finer adjustments, ensuring you achieve a balance between comfort and control.

Step 13: Test the Suspension Fork

Once the fork is rebuilt and reinstalled, it’s crucial to test the suspension to ensure it is functioning correctly.
Push down on the fork and check for smooth movement. If you feel any resistance or stiction, check that the lower leg assembly is correctly installed and that the suspension fluid is at the correct level.

Troubleshooting Common Issues

Even after rebuilding your DH38 Race fork, issues can arise. Here are some common problems and how to address them:

Problem 1: Fork Is Too Soft or Too Firm

Cause: Incorrect suspension fluid level or improper spring setup.
Solution: Double-check the fluid level and ensure the spring is correctly adjusted for your weight and riding style.

Problem 2: Fork Leaking Oil

Cause: Damaged seals or O-rings.
Solution: Replace any worn seals or O-rings with new ones from your service kit.

Problem 3: Poor Rebound or Compression Performance

Cause: Incorrect adjustment or contamination inside the damper.
Solution: Clean the damper internals and reset the rebound/compression settings to the factory specifications.

Customization and Optimization

For riders looking to get the most out of their DH38 Race fork, customization can improve both comfort and performance.

Adjusting the Air Pressure

The DH38 Race fork can be fine-tuned by adjusting the air pressure in the spring unit. For aggressive riders, higher pressure will provide more support, while lighter riders may prefer lower pressure for a more plush feel.

Upgrading to Performance Seals

Consider upgrading to high-performance seals for better oil retention and a smoother ride. These seals can improve the overall responsiveness of your fork.

Compatibility with Other Drivetrain Components

The DH38 Race fork is designed to be compatible with a wide range of drivetrain components. However, it’s important to ensure that the fork’s axle and wheel sizes align with your bike’s specifications. The DH38 Race fork is typically used with 27.5” or 29” wheels, so ensure that your frame and wheelset are compatible.

Key Compatibility Considerations:

Axle Type: Make sure the fork’s axle type matches your bike’s dropout standard (e.g., quick-release or through-axle).
Steerer Tube Diameter: Check that the steerer tube diameter fits your bike’s head tube.
Brake Mount Compatibility: Ensure that the fork supports your chosen brake mount (e.g., Post Mount or IS).

By following these steps, you can successfully rebuild your DH38 Race suspension fork, maintaining its performance and ensuring a smooth, controlled ride every time you hit the trails.