Performing an oil change on the Marzocchi Bomber Air Trunnion [paid link] rear shock is a crucial part of bike maintenance that ensures smooth performance and longevity. Regular maintenance, including oil changes, helps preserve the shock’s responsiveness, dampening efficiency, and overall functionality. This guide will take you through the detailed steps of performing an oil change on your Bomber Air Trunnion [paid link], helping you maintain peak [paid link] performance for your bike.

Tools Required

• 5mm Allen wrench [paid link]
• 8mm Allen wrench [paid link]
• 10mm socket wrench
• Torque wrench [paid link]
• Plastic syringe or oil pump
• Marzocchi Bomber Air [paid link] oil (recommended for the shock)
• Towel or clean cloth
• Suspension oil drain pan
• Small brush for cleaning
• Gloves (optional for better hygiene)

Preparing the Bike

Before diving into the oil change process, it’s essential to prepare your bike and rear shock properly.

1. Remove the rear shock from the bike: Start by detaching the rear shock from the frame. Use a 5mm Allen wrench to remove the bolts securing the shock. Gently slide the shock out of its mounts and place it on a clean, stable surface.
2. Secure the shock: Set the shock on a towel or cloth to protect the surface from scratches while you work.

Disassembling the Bomber Air Trunnion Rear Shock

Now that the shock is off the bike, follow these steps to begin disassembly:

1. Remove the air valve cap: Using a 10mm socket wrench, remove the cap on the air valve located at the top of the shock. This will release any remaining air pressure.
2. Unscrew the damper side cover: Use a 5mm Allen wrench to remove the screws holding the damper side cover in place. Gently remove the cover to expose the internal components of the shock.
3. Drain the existing oil: Position a drain pan underneath the shock and slowly drain the old oil. You can tilt the shock gently to ensure complete drainage.

Cleaning the Components

Once the oil has been drained, it is important to clean all the components to remove any debris or old oil residues.

1. Clean the damper piston: Use a small brush and clean rag to wipe away any dirt or old oil from the damper piston. Be careful not to damage any internal seals.
2. Inspect the seals: Check the seals inside the damper body for any signs of wear or damage. If any seals look compromised, replace them to avoid future leaks and performance issues.

Refilling with Fresh Oil

The next step is to refill the shock with fresh Marzocchi Bomber Air [paid link] oil to ensure optimal shock performance.

1. Prepare the oil syringe: Use a plastic syringe or an oil pump to fill the shock with the recommended amount of fresh oil. Fill the damper side with oil until the syringe is emptied.
2. Reassemble the damper side cover: Carefully reinstall the damper side cover and secure it with the 5mm Allen screws. Ensure that the cover is tightly screwed in to prevent any oil leakage.

Reinstalling the Shock

Once the oil change is complete and the shock has been reassembled, it is time to reinstall it onto the bike.

1. Reattach the shock to the frame: Align the shock back into its mounting points on the frame. Use the 5mm Allen wrench to fasten the mounting bolts securely.
2. Check for proper air pressure: Before fully tightening everything, check the shock’s air pressure using a shock pump. Ensure the air pressure is set according to the specifications provided by Marzocchi.
3. Torque the bolts: Use a torque wrench [paid link] to tighten the mounting bolts to the recommended torque value for your specific frame and shock combination. This step ensures that the shock is securely mounted and will perform optimally.

Final Inspection and Testing

After the shock is reinstalled, perform a final check and test ride.

1. Cycle the shock: Before riding, manually compress the shock a few times to make sure the oil is properly distributed and that there are no unusual noises or resistance.
2. Check for leaks: Inspect the shock for any signs of oil leakage around the seals and fittings.
3. Test ride: Take your bike for a short test ride to ensure the shock is functioning smoothly. Pay attention to any changes in ride quality or performance that may indicate a need for further adjustments.

Troubleshooting Common Set-Up Issues

During the oil change process, you may encounter a few common issues. Here’s how to address them:

1. Shock not holding air pressure: If your shock loses air after the oil change, double-check the air valve and seals. A damaged seal can lead to air leakage, requiring replacement.
2. Oil leakage: If you notice oil leakage around the damper side cover, ensure that it was properly sealed and tightened during reassembly. Also, check the internal seals for wear.
3. Unusual noise or feel: If the shock feels spongy or produces odd noises after reassembly, ensure that the shock was properly refilled with oil and that no debris is obstructing the internal components.

Customization and Optimization for Better Performance

To optimize the performance of your Marzocchi Bomber Air Trunnion rear shock, consider the following customization options:

1. Adjusting the air pressure: Fine-tune the air pressure to match your rider weight and riding style. A shock pump with a pressure gauge is essential for this adjustment.
2. Rebound and compression adjustments: Adjust the rebound and compression settings to suit your preference and riding conditions. Fine-tuning these settings can significantly improve the ride feel and handling of your bike.
3. Upgrade the oil: For advanced riders, experimenting with different types of oil can change the damping characteristics, offering a more custom ride. Consult Marzocchi’s recommendations or speak with a professional for advice.

Comparing with Similar Models

While the Bomber Air Trunnion is an excellent choice for most mountain and enduro riders, it’s important to consider similar models to determine the best fit for your needs:

1. Fox Float DPX2: The Fox Float DPX2 offers advanced damping technology and a more refined design, making it a great choice for riders seeking a more premium shock.
2. RockShox Super Deluxe: RockShox’s Super Deluxe features a similar air spring setup but has a more adjustable damper. It’s an excellent option for those looking for increased control and fine-tuning.

Both the Fox Float and RockShox Super Deluxe offer features comparable to the Bomber Air Trunnion, with slight differences in design and performance. Riders who prioritize easy maintenance and durability might prefer the Bomber Air Trunnion, while those seeking maximum adjustability may lean towards the Fox or RockShox options.

Compatibility with Other Drivetrain Components

The Bomber Air Trunnion rear shock is compatible with a wide range of mountain bike frames, especially those designed for aggressive trail and enduro riding. It is important to verify frame compatibility with your bike’s rear suspension mounting system before installation. The trunnion mounting system provides more precise suspension movement and is designed for frames with compatible shock mount points. Be sure to check your bike’s geometry and mounting specifications to ensure the Bomber Air Trunnion fits securely.