A Comprehensive Guide to Bomber CR Trunnion Rear Shocks

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The Marzocchi Bomber CR Trunnion [paid link] rear shock is a highly regarded component known for its durability, performance, and reliability. Designed for aggressive mountain biking and enduro riding, it offers excellent control and adjustability. This guide will provide you with all the necessary information on how to install, adjust, maintain, troubleshoot, and optimize the Bomber CR Trunnion [paid link] rear shock for superior performance.

Installation of Bomber CR Trunnion Rear Shock

Installing the Marzocchi Bomber CR Trunnion rear shock is straightforward, but it requires attention to detail to ensure proper setup. Here are the key steps for installation:

Tools Required

  • Torque wrench [paid link]
  • 5mm and 6mm Allen wrenches [paid link]
  • Shock pump
  • Grease
  • Socket set (if needed)
  • 8mm spanner for mounting bolts

Installation Steps

  1. Remove the Existing Rear Shock
    Before installing the new shock, ensure that the rear wheel is removed, and the rear triangle of the bike is suspended. Use your 5mm and 6mm Allen wrenches [paid link] to remove the mounting bolts securing the old shock in place. Be careful not to damage the frame during this process.
  2. Prepare the Bomber CR Trunnion Shock
    Apply a thin layer of grease to the shock’s mounting hardware. This will ensure smooth installation and prevent corrosion over time. Check that the trunnion mounting hardware is compatible with your frame’s geometry.
  3. Install the Bomber CR Trunnion Shock
    Place the shock into the rear triangle, aligning the trunnion mounts with the frame’s shock mounts. Secure the shock with the appropriate mounting bolts, ensuring they are torqued to the manufacturer’s recommended settings. Use your torque wrench [paid link] to ensure the bolts are tightened to spec.
  4. Reinstall the Rear Wheel
    Once the shock is securely mounted, reinstall the rear wheel. Double-check the installation to ensure all components are properly aligned and that the shock is correctly seated in its mount.
  5. Adjust the Sag
    Using a shock pump, adjust the air pressure in the shock to set the correct sag based on your rider weight and riding style. A sag of around 30% is ideal for most riders, but this can vary depending on personal preferences and terrain.

Adjusting the Bomber CR Trunnion Rear Shock

The Marzocchi Bomber CR Trunnion shock comes equipped with a variety of adjustments to fine-tune its performance for different riding conditions. These adjustments include rebound, compression damping, and air pressure settings. Here’s how to make the most of these settings:

Rebound Adjustment

The rebound adjustment controls how quickly the shock returns after being compressed. This is crucial for maintaining traction and control on rough terrain.

  • Turn the rebound dial clockwise to slow down the rebound (for fast and aggressive terrain).
  • Turn the dial counterclockwise to increase rebound speed (for smoother trails).

Start with a mid-range setting and adjust based on your riding conditions. Slower rebound can improve control on technical descents, while faster rebound may be better for smoother terrain.

Compression Damping

The Bomber CR Trunnion shock features a high-speed compression adjustment that allows you to fine-tune the shock’s resistance to compression under load.

  • Increase compression by turning the dial clockwise to provide more support during hard hits or aggressive riding.
  • Decrease compression by turning the dial counterclockwise for a more plush feel over smaller bumps.

Adjust the compression settings depending on the trail and the type of riding you are doing. A firmer compression setting is beneficial for aggressive, rough terrain, while a softer setting works well for cross-country or trail riding.

Air Pressure

Proper air pressure in the shock is vital for maintaining the correct sag and ensuring optimal shock performance. Use a shock pump to adjust the air pressure, and ensure the shock is inflated to the recommended PSI for your weight and riding style.

Maintenance of the Bomber CR Trunnion Rear Shock

Proper maintenance is essential to keep your Bomber CR Trunnion rear shock functioning at its best. Routine checks and servicing will prolong the life of your shock and ensure a smooth ride.

Cleaning

  • Regularly clean the shock after each ride to prevent dirt, mud, and debris from building up. Use a soft brush and water to remove dirt from the shock body, and dry it thoroughly.
  • Avoid using harsh solvents or high-pressure washers, as these can damage the shock seals.

Inspection

  • Inspect the shock for any signs of wear or damage, including oil leakage, bent or broken mounts, or damage to the shock body. If any issues are detected, it’s essential to address them immediately to avoid further damage.
  • Check the mounting bolts periodically to ensure they are properly torqued.

Lubrication

  • Apply a light layer of grease to the shock mounts to prevent corrosion and ensure smooth movement.
  • Lubricate the shock’s air valve and damping controls lightly to keep them functioning smoothly.

Servicing

  • The Bomber CR Trunnion shock requires occasional servicing, including oil changes and seal replacements. Marzocchi recommends a full service every 50-100 hours of riding, or once a year, depending on your riding conditions.
  • If you’re not familiar with shock servicing, it’s advisable to take your shock to a professional for a complete overhaul.

Troubleshooting Common Set-Up Issues

While the Bomber CR Trunnion rear shock is designed for durability and performance, you may encounter a few common issues during setup or use. Here’s how to troubleshoot them:

Issue 1: Lack of Traction or Comfort

If the shock feels too harsh or doesn’t provide enough traction, the issue may be related to incorrect air pressure or rebound settings.

  • Solution: Double-check the air pressure and adjust the rebound setting to ensure the shock is performing optimally. Lowering the air pressure slightly may provide a more comfortable ride on rough terrain.

Issue 2: Shock Bottoming Out

If the shock feels like it’s bottoming out too frequently, you may not have enough compression damping or air pressure.

  • Solution: Increase the compression damping and/or raise the air pressure to reduce bottoming out. Additionally, check for proper sag, as too much sag can lead to excessive compression.

Issue 3: Leaking Oil

Oil leakage can occur if the shock seals are damaged or if the shock is over-pressurized.

  • Solution: Inspect the seals for wear and replace them if necessary. If oil leakage persists, it’s best to have the shock serviced by a professional.

Customization and Optimization for Better Performance

The Marzocchi Bomber CR Trunnion rear shock offers multiple avenues for customization, enabling riders to fine-tune their setup for specific riding needs.

  • Fine-Tune Air Pressure: Tailor the shock’s air pressure based on your weight, riding style, and terrain. A higher air pressure will provide more support for aggressive riding, while a lower air pressure offers a more plush feel.
  • Adjust Compression for Terrain: Customizing the compression settings based on terrain will improve performance. On technical, rocky descents, increase compression for better control. On smoother trails, reduce compression for a more comfortable, responsive ride.

Comparison with Similar Models

When comparing the Bomber CR Trunnion shock to other similar models, such as the RockShox Super Deluxe or Fox Float DPX2, a few key differences stand out:

  • Marzocchi Bomber CR Trunnion: Known for its simple, straightforward design and durable build, it offers excellent value for money. Its rebound and compression adjustments are easily accessible, making it an ideal choice for riders seeking reliability over an array of features.
  • RockShox Super Deluxe: Offers a wider range of fine-tuning options and features such as the Solo Air system, which is designed for quick and easy setup.
  • Fox Float DPX2: While it offers more advanced features, such as the EVOL air spring and dynamic rebound adjustments, it comes at a higher price point.

The Bomber CR Trunnion is a great option for riders seeking a balance between performance and cost, especially for aggressive riders who prioritize durability over excessive customization.

Compatibility with Other Drivetrain Components

The Bomber CR Trunnion rear shock is compatible with most modern mountain bike frames that feature a trunnion mount system. Before installation, it’s essential to check the specifications of your bike’s rear triangle to ensure compatibility with the shock’s dimensions.

  • Frame Mounting: Ensure your frame is designed for a trunnion-mount shock, as it has different mounting points compared to traditional shocks.
  • Suspension Fork Compatibility: The Bomber CR Trunnion works well in conjunction with Marzocchi or other high-performance suspension forks. However, it’s essential to ensure the overall suspension balance is maintained by matching the rear shock with a compatible fork for optimal performance.