The Marzocchi Bomber Air Trunnion rear shock is a robust and reliable component that can elevate the performance of any road bike. However, like all precision-engineered parts, it can occasionally encounter issues. Whether you’re experiencing issues with suspension feel, performance, or setup, this guide will provide you with a comprehensive troubleshooting process to help you identify and resolve the most common Bomber Air Trunnion rear shock problems.

Understanding the Bomber Air Trunnion Rear Shock

Before diving into troubleshooting, it is crucial to understand the components and functions of the Bomber Air Trunnion rear shock. The Bomber Air Trunnion is designed to provide superior suspension performance for aggressive riding. It features a lightweight air spring system paired with a trunnion mount, providing a balance of comfort, control, and responsiveness. This system is engineered for durability, but as with any air shock, maintaining optimal performance requires attention to detail in setup and maintenance.

Common Bomber Air Trunnion Rear Shock Issues

1. Lack of Rebound Control

Symptoms:

• The shock does not return to its original position after compressing.
• The rear of the bike may feel bouncy or overly stiff.

Potential Causes and Solutions:

• Incorrect Rebound Damping Settings: The Bomber Air Trunnion includes an adjustable rebound damping dial. If the rebound is too fast, the shock will not return smoothly after compression. To correct this, adjust the rebound knob to a slower setting.
• Oil Viscosity Issues: Over time, the oil inside the shock can degrade, affecting rebound performance. If adjusting the rebound knob doesn’t resolve the issue, it may be time to service the shock and replace the oil.

2. Air Leaks

Symptoms:

• The shock feels softer than usual and doesn’t return to its original pressure.
• Pressure loss can occur suddenly, resulting in poor suspension performance.

Potential Causes and Solutions:

• Damaged Seals: Air leaks are often caused by worn or damaged seals. Check the air valve and seal for any visible damage or wear. If seals are compromised, they need to be replaced.
• Incorrect Pressure Settings: Ensure that the shock is properly inflated to the recommended air pressure for your rider weight and riding style. Under-inflation can cause a loss of performance, while over-inflation might lead to excessive stiffness.

3. Sag Issues

Symptoms:

• The bike feels either too soft or too stiff when riding.
• The rider may notice that the suspension is not effectively absorbing impacts, leading to a harsh ride.

Potential Causes and Solutions:

• Incorrect Sag Setting: The Bomber Air Trunnion is designed to have a specific amount of sag based on rider weight and riding style. If you’re experiencing sag issues, check the sag by pressing down on the bike while it is in a neutral position. Adjust the air pressure until you achieve the proper sag, typically between 25-30% of the shock’s total stroke.
• Damaged Air Spring: If adjusting the air pressure does not resolve the sag issue, the air spring may be damaged or leaking. In such cases, servicing or replacing the air spring might be necessary.

4. Shock Sticking or Binding

Symptoms:

• The shock feels resistant to compression.
• There is a noticeable sticking or jerky movement during suspension travel.

Potential Causes and Solutions:

• Dirty or Contaminated Bushings: Over time, dirt and debris can accumulate in the bushings or pivot points, causing friction and binding. Clean and lubricate the bushings regularly to maintain smooth shock movement.
• Misalignment of Mounting Points: If the shock is misaligned in the trunnion mount or linkages, it may result in binding. Check for any misalignment in the suspension frame and shock mount area, and ensure everything is properly torqued.

5. Excessive Bottoming Out

Symptoms:

• The shock bottoms out during impacts, providing a harsh, uncomfortable ride.
• The bike may feel unstable or unresponsive when hitting larger obstacles.

Potential Causes and Solutions:

• Too Little Air Pressure: If the shock is under-inflated, it may bottom out during compression. Check the recommended pressure for your rider weight and adjust accordingly.
• Insufficient Compression Damping: The Bomber Air Trunnion features adjustable compression damping. If the shock bottoms out easily, try adjusting the compression dial to increase damping and prevent bottoming out.
• Worn-out Damper: If the shock is still bottoming out after adjusting the air pressure and damping settings, the damper may be worn and require servicing or replacement.

6. Noise from the Rear Shock

Symptoms:

• A squeaking, creaking, or clunking noise emanates from the rear shock during suspension movement.

Potential Causes and Solutions:

• Lack of Lubrication: The shock’s pivot points and bushings require regular lubrication to prevent friction. Apply lubricant to the necessary parts to reduce noise.
• Loose Components: Check the shock bolts and mounting hardware for tightness. A loose mount or link can cause noises during suspension movement.

Bomber Air Trunnion Rear Shock Maintenance Tips

To prevent common issues and ensure optimal performance, regular maintenance is essential for the Bomber Air Trunnion rear shock. Follow these maintenance tips:

• Regularly Check Air Pressure: Perform regular checks on the shock’s air pressure to ensure it remains within the recommended range for your weight and riding style.
• Lubricate Bushings and Pivot Points: Apply lubricant to the shock’s bushings and pivot points every 30-40 hours of riding to reduce friction and prevent noise.
• Inspect Seals and Bushings: Check seals and bushings for wear every 100-150 hours of riding or after riding in harsh conditions (e.g., wet, muddy trails).
• Servicing: Every 200-300 hours of riding, consider servicing the shock to replace oil, seals, and other wear parts to maintain peak performance.

Conclusion

The Marzocchi Bomber Air Trunnion rear shock is a high-performance component that, when properly maintained and tuned, can offer exceptional suspension performance. By understanding and addressing common issues such as rebound control problems, air leaks, sag issues, and noise, riders can ensure their shocks operate smoothly and effectively. Regular maintenance and timely servicing will extend the life of the shock and improve the overall riding experience.