DNM TRU-3 Trunnion Spring Suspension Mountain Bike Rear Shock Absorber

Introduction

This manual provides essential information for the proper installation, operation, and maintenance of your DNM TRU-3 Trunnion Spring Suspension Rear Shock Absorber. Designed for hardcore mountain bike riders, the TRU-3 features a robust alloy trunnion structure and a reliable coil spring system, ensuring stable and comfortable riding even in harsh environments. Please read this manual thoroughly before use to ensure optimal performance and safety.

Specifications

Setup and Installation

Proper installation and initial setup are crucial for the performance and longevity of your shock absorber. If you are unsure about any steps, please consult a professional bicycle mechanic.

1. Installation:
   • Ensure the shock absorber matches your bicycle frame's required length (185mm or 205mm) and mounting type (trunnion).
   • Mount the shock absorber securely to your bicycle frame using the appropriate hardware. The top mount is M10*54mm and the bottom mount is 24*8mm, with a 12mm eyelet diameter and 8mm bushing diameter/24mm length.
   • Double-check all bolts and fasteners to ensure they are tightened to the manufacturer's recommended torque specifications for your bike frame.
2. Preload/Compression Adjustment (Blue Knob):

   The blue knob on the upper part of the shock allows for preload and compression adjustment, controlling the shock's softness or hardness. This helps in quickly adapting to various road conditions.

   • Turning the blue knob towards the "-" sign reduces the preload value, making the damping effect softer. This is suitable for smoother terrains or when a more plush ride is desired.
   • Increasing the preload (turning towards the "+" sign) makes the shock harder. A larger preload value helps prevent the damping effect from negatively impacting power output during pedaling, especially on climbs or when seeking a more responsive feel.

   

   

3. Rebound Adjustment (Red Knob):

   The red knob located at the bottom of the shock controls the rebound speed, which is how quickly the shock returns to its original position after compression. This is essential for maintaining tire contact with the ground and absorbing successive bumps.

   • Turning the red knob counter-clockwise slows down the rebound speed. This is generally preferred for rougher, more technical terrain to prevent the wheel from kicking up.
   • Turning the red knob clockwise speeds up the rebound. A faster rebound is often used for smoother trails or when you need the shock to recover quickly for successive impacts.

   

   

Operating Your Shock Absorber

The DNM TRU-3 is designed to provide efficient shock absorption and improve control stability across various terrains. Utilize the adjustment features to fine-tune your riding experience.

• Dynamic Adjustment: Adjust preload/compression and rebound settings based on the terrain and your riding style. Softer settings are generally better for absorbing small bumps and maintaining traction, while firmer settings provide more support for jumps and aggressive riding.
• High-Frequency Bumps: With proper damping adjustment, the TRU-3 effectively handles high-frequency bumps, ensuring a smoother ride and better control.
• Efficient Shock Absorption: The high-strength and high-quality springs significantly reduce vibration and impact force, enhancing comfort and control.

Maintenance

Regular maintenance will extend the life and performance of your DNM TRU-3 shock absorber.

• Cleaning: After each ride, especially in dirty or wet conditions, clean the shock body and shaft with mild soap and water. Avoid high-pressure washers directly on seals.
• Inspection: Periodically inspect the shock for any signs of damage, leaks, or excessive wear on the seals and bushings. Check mounting bolts for tightness.
• Lubrication: Keep the exposed shaft clean and lightly lubricated with a suspension-specific lubricant to protect the seals and ensure smooth operation.
• Professional Service: For internal maintenance or if you notice significant performance degradation, it is recommended to have the shock serviced by an authorized DNM service center or a qualified bicycle mechanic.

Troubleshooting

Here are some common issues and their potential solutions:

• Loss of Damping: If the shock feels overly bouncy or bottoms out easily, check your preload/compression settings. If the issue persists, the shock may require professional servicing to check for internal fluid loss or seal wear.
• Excessive Sag: Ensure your spring rate is appropriate for your weight and riding style. Adjust preload to achieve the desired sag. If sag cannot be set correctly, a different spring rate might be needed.
• Noisy Operation: Squeaking or clunking noises can indicate loose mounting bolts, worn bushings, or internal issues. Check all fasteners and inspect bushings. If the noise continues, professional inspection is advised.
• Oil Leaks: Small amounts of oil residue on the shaft are normal. However, if you observe significant oil leakage, this indicates a seal failure and requires immediate professional servicing.

User Tips

• Match Shock to Bike: Always ensure the shock length and spring rate are compatible with your specific bike frame and your body weight for optimal performance and safety.
• Experiment with Settings: Don't be afraid to experiment with the preload/compression and rebound adjustments. Small changes can significantly alter the ride feel. Keep a record of your preferred settings for different terrains.
• Regular Checks: Before each ride, quickly check the shock for any visible damage, proper function, and ensure all mounting bolts are secure.

Warranty and Support

For warranty claims, technical support, or service inquiries, please contact your retailer or the official DNM distributor. Keep your proof of purchase handy as it may be required for warranty services.

For further assistance, you may also refer to the official DNM website or contact their customer service directly.