The Marzocchi Bomber Air Trunnion [paid link] is a high-performance rear shock designed to provide excellent suspension performance and handling. Whether you’re riding on rough terrain or tackling more technical trails, tuning this shock can significantly enhance your riding experience. This guide will walk you through everything you need to know to install, adjust, maintain, and troubleshoot your Bomber Air Trunnion [paid link] rear shock.

Installation of the Bomber Air Trunnion

Installing your Bomber Air [paid link] Trunnion rear shock correctly is crucial for both safety and optimal performance. Follow the steps below to ensure a proper installation:

1. Prepare Your Bike
   Before you begin, make sure your bike is secure. Use a work stand to elevate the rear end, making it easier to access the shock. You’ll also want to remove any accessories or components that might obstruct your access to the shock mount points.
2. Remove the Old Shock
   If replacing an existing shock, carefully unbolt it from the frame and remove it. Depending on your frame design, this may involve removing the lower and upper shock bolts.
3. Install the Bomber Air [paid link] Trunnion
   Align the Bomber Air Trunnion with the shock mounts. Ensure the correct orientation of the shock, making sure the air valve is facing outward for easy access. Insert the upper shock bolt through the shock mount and tighten it to the manufacturer’s recommended torque specification. Repeat the process for the lower mount. Ensure the shock is fully seated in the trunnion mounts.
4. Check for Proper Alignment
   Once installed, double-check the alignment of the shock and ensure it moves smoothly when compressed. This will help avoid any rubbing or interference with other components.

Adjustment of the Bomber Air Trunnion

Adjusting the Bomber Air Trunnion shock is key to tailoring its performance to your riding style and the terrain you’re tackling. Here’s how to adjust the shock for optimal performance:

1. Set the Sag
   The first step in adjusting your Bomber Air Trunnion is setting the sag. The sag refers to how much the shock compresses under your body weight. To find the ideal sag:
   • Inflate the shock to the recommended pressure, typically listed on the shock’s sticker.
   • Mount your bike and gently bounce on it to settle the suspension.
   • Measure the amount of travel the shock compresses under your weight. Aim for around 25-30% of the shock’s total travel for optimal performance.
2. Fine-Tune the Rebound
   The rebound adjuster controls how quickly the shock returns to its fully extended position after compression. To adjust rebound:
   • Turn the rebound knob counterclockwise to increase the rebound speed (faster return).
   • Turn it clockwise to slow down the rebound (slower return).
   • Start by setting it to the middle setting and adjust based on your riding conditions.
3. Adjust the Compression
   The Bomber Air Trunnion features separate high-speed and low-speed compression adjusters. These adjust how the shock reacts to different terrain and impacts.
   • Low-speed compression affects the shock’s reaction to rider movement and small bumps. Increase compression to make the ride stiffer for improved control on technical terrain, or decrease it for a softer feel.
   • High-speed compression affects how the shock responds to larger impacts such as drops or big hits. Start by setting the high-speed compression to a lower setting and adjust based on the terrain you encounter.
4. Air Pressure Adjustment
   Fine-tune the air pressure based on your riding weight, sag, and preferred shock feel. To adjust the air pressure:
   • Use a shock pump to add or release air from the shock.
   • If you’re too soft or sagging too much, increase the pressure slightly. Conversely, if the ride feels too stiff, reduce the pressure.
   • Recheck your sag after adjusting the air pressure.

Maintenance of the Bomber Air Trunnion

Proper maintenance ensures the longevity of your Bomber Air Trunnion rear shock. Here’s how to keep it running smoothly:

1. Clean After Every Ride
   Clean the shock after each ride to prevent dirt and debris from entering the seals. Use a clean, damp cloth to wipe down the shock body and remove any buildup of grime. Avoid using harsh chemicals that could damage the shock.
2. Check for Leaks
   Regularly inspect the shock for any signs of air or oil leakage. If you notice any oily residue around the seals, it may indicate a seal failure, requiring a service.
3. Lubricate the Seals
   Occasionally, apply a small amount of lubricant to the shock’s seals to keep them functioning smoothly. This helps prevent dirt buildup and ensures a smooth, responsive ride.
4. Check the Bolts
   Periodically check the shock mounting bolts to ensure they are secure and torqued to the manufacturer’s specifications. Loose bolts can compromise the shock’s performance and safety.
5. Service the Shock
   If you notice a decrease in performance, or if the shock begins to feel sluggish or unresponsive, consider sending it in for a professional service. The shock should be serviced every 1-2 years depending on usage.

Troubleshooting Common Set-Up Issues

Even the best rear shock can present issues. Below are some common problems you may encounter with your Bomber Air Trunnion and how to fix them:

1. Too Much Sag
   If you find that your shock compresses too much under your weight, this may indicate that the air pressure is too low. Inflate the shock to the recommended pressure and check the sag again.
2. Harsh Ride or Bottoming Out
   A harsh ride or bottoming out may occur if the compression settings are too stiff. Try reducing the compression settings, especially the high-speed compression, to make the shock more responsive to impacts.
3. Excessive Rebound Speed
   If the shock feels too bouncy or is coming back too quickly, slow down the rebound by turning the rebound knob clockwise. This will allow the shock to return more slowly and offer a more controlled ride.
4. Leakage or Oil Spillage
   If you notice oil leaking around the seals or any other signs of fluid loss, it’s likely that the shock needs a rebuild. This should be addressed by a professional to prevent further damage.

Customization and Optimization for Better Performance

To get the best out of your Bomber Air Trunnion, consider the following customizations and optimizations:

1. Fine-Tune the Damping
   Experiment with both high-speed and low-speed compression settings based on the type of riding you’re doing. For smoother trails, reduce compression settings for a more plush feel. For more aggressive or technical riding, increase compression to firm up the shock and provide better support.
2. Adjust for Different Terrain
   For downhill or rough terrain, increasing the low-speed compression can help with control and minimize pedal bob. On smoother trails, you might want to reduce compression to maximize comfort.
3. Upgrade the Air Sleeve
   Some riders choose to upgrade the air sleeve or swap out internal parts for more specific tuning. This can further refine your shock’s performance, making it more tailored to your needs.

Comparison with Similar Models

When comparing the Bomber Air Trunnion to other rear shocks, it’s essential to consider the type of terrain you ride and the features you need.

• Fox Float X2: The Fox Float X2 offers a more adjustable platform with a wider range of tuning options, including an extra low-speed compression adjustment. However, it’s typically more expensive than the Bomber Air Trunnion, which provides excellent performance at a more accessible price point.
• RockShox Super Deluxe: The Super Deluxe also features a trunnion mount design and offers adjustable rebound and compression settings, similar to the Bomber Air Trunnion. The Bomber Air Trunnion, however, is generally considered a bit more rugged [paid link] and easier to maintain with fewer complex parts.

Compatibility with Other Drivetrain Components

The Bomber Air Trunnion is compatible with most modern mountain bike frames equipped with trunnion mount suspension designs. However, it’s important to confirm that your frame is designed for a trunnion shock before installation. Additionally, ensure your bike’s overall geometry and shock travel align with the Bomber Air Trunnion’s specifications to avoid any compatibility issues with your drivetrain or other suspension components.