The Arma V3 [paid link] rear shock from EXT is a high-performance suspension component designed for riders seeking optimal control and comfort on challenging terrains. One of the critical factors in ensuring your rear shock delivers its best performance is achieving the correct sag. Sag refers to the amount of compression a shock undergoes when you sit on the bike, and it significantly influences the bike’s handling and comfort.
This guide will take you through the step
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-by-step process of setting up your rear shock sag for the Arma V3 [paid link], including the tools required, the necessary adjustments, troubleshooting tips, and optimization strategies for improved performance.
Tools Required
- Shock pump with a pressure gauge
- Tape measure or ruler
- Marker or piece of tape for measurement marking
- A second person to help (optional, but recommended)
- A floor pump (if necessary for other adjustments)
Understanding Sag and Its Importance
Before diving into the setup process, it’s important to understand what sag is and why it matters. The correct amount of sag ensures that the rear shock performs as intended by the manufacturer, balancing comfort with efficient pedaling and handling.
- Too little sag can result in a harsh ride, as the shock remains overly stiff and doesn’t absorb impacts effectively.
- Too much sag can cause the shock to bottom out too easily, reducing the bike’s control and stability on rough trails.
The Arma V3 rear shock is designed to offer a specific range of sag depending on the rider’s weight and riding style. Typically, the recommended sag is around 25-30% of the shock’s total travel.
Step-by-Step Sag Setup for Arma V3
Step 1: Prepare Your Bike
Start by ensuring the bike is stable and positioned on a level surface. It is recommended to have the bike on a stand, but if you don’t have one, ensure it is securely propped up.
Step 2: Measure the Shock’s Total Travel
The Arma V3 rear shock typically features a specific amount of travel (usually 150mm or 160mm, depending on your model). You will need to know this to determine the correct sag percentage. Measure the shock’s total travel from the top of the shock body to the bottom of the stroke, ensuring that this distance is accurately recorded.
Step 3: Set Initial Air Pressure
Use a shock pump to set the air pressure based on your weight and riding style. EXT provides a baseline air pressure recommendation in the Arma V3 manual, but a general starting point is around 200 psi for a rider of average weight. This can be adjusted once the sag measurement is complete.
Step 4: Mark the O-ring Position
Before you begin the sag test, place the O-ring or a piece of tape on the shaft of the shock. This will serve as a reference point for how much the shock compresses under your weight. Make sure the O-ring is positioned at the top of the shock shaft, right near the seal.
Step 5: Sit on the Bike
Once your shock is inflated and the O-ring is in place, carefully sit on the bike in your normal riding position. It’s crucial to maintain a neutral, relaxed posture to mimic real riding conditions. If possible, have a second person help by holding the bike steady while you do this.
Step 6: Check the Sag
After sitting on the bike, check the position of the O-ring relative to the top of the shock. Measure the distance the O-ring has moved, and compare it to the shock’s total travel. The ideal sag is between 25-30% of the total travel.
For example:
- If your shock has 150mm of travel, your target sag would be between 37.5mm and 45mm.
- If your shock has 160mm of travel, the ideal sag would fall between 40mm and 48mm.
Step 7: Adjust the Air Pressure
If the sag is too little (less than the recommended range), add air to the shock. If it’s too much (more than the recommended range), release some air. Recheck the sag after making each adjustment and continue fine-tuning until you achieve the ideal sag.
Step 8: Test the Setup
Once the sag is dialed in, take your bike for a short ride to test the setup. Pay attention to how the bike handles over bumps and during pedaling. If the ride feels too harsh or too soft, you may need to make further small adjustments to the air pressure.
Troubleshooting Common Sag Setup Issues
Issue 1: Sag Too Low
If you find that your sag is too low after sitting on the bike, it typically means the shock’s air pressure is too high. Release some air and check the sag again. If the pressure adjustment doesn’t resolve the issue, it might indicate that the shock is undersized for your weight or riding style, and you may need to consult with a suspension technician for further adjustments.
Issue 2: Sag Too High
If the sag is too high, the shock is too soft, causing excessive compression. This can lead to bottoming out on rough terrain. Increase the air pressure to make the shock stiffer. If increasing the pressure doesn’t help, consider adjusting the volume spacer settings in the shock.
Issue 3: O-Ring Not Moving
If the O-ring does not move after riding, this could be an indication of excessive air pressure or a lack of preload on the shock. Review your air pressure settings and ensure that the shock is properly adjusted.
Customization and Optimization for Better Performance
While the Arma V3 is designed for top-tier performance out of the box, there are several additional ways to optimize your setup.
- Volume Spacers: Adjusting the number of volume spacers in your shock can change its progression curve, making it either more linear or more progressive. Adding more spacers can prevent bottoming out, while fewer spacers can improve small-bump sensitivity.
- Rebound and Compression Damping: The Arma V3 features adjustable rebound and compression damping. Fine-tuning these settings based on trail conditions and rider preference can enhance both comfort and control.
Compatibility with Other Drivetrain Components
The Arma V3 rear shock is designed to integrate seamlessly with a variety of high-end drivetrain components. Whether you’re pairing it with a Shimano, SRAM, or Campagnolo drivetrain, compatibility is rarely an issue, as long as the bike’s frame is designed to accommodate a rear shock of similar dimensions and specifications.
Frame Compatibility
Ensure that your bike frame is designed to work with the Arma V3 rear shock in terms of shock eyelet size and mounting hardware. While the shock itself is adjustable and versatile [paid link], compatibility with the frame is crucial for achieving optimal performance and safety.
Conclusion
Setting up the rear shock sag for the Arma V3 is an essential process that will directly influence the performance and comfort of your bike. By following these steps, you can ensure that your shock is set up to handle a variety of terrains, from rough trails to smooth cross-country rides. Make sure to periodically check your shock setup, especially after changing riding conditions or adjusting your gear, to maintain top-notch performance throughout the life of your Arma V3 rear shock.