DIY Rear Derailleur Adjustment for RED eTap AXS D2 (12-speed) on Gravel Bikes

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The SRAM RED eTap AXS D2 12-speed rear derailleur is a high-performance component designed for the demands of modern gravel biking. Ensuring that it is properly adjusted is crucial to achieving smooth shifting performance and preventing wear or damage. This guide walks you through the steps to install, adjust, and maintain the RED eTap AXS D2 rear derailleur on your gravel bike, along with troubleshooting tips for common issues and ways to optimize the system for the best possible performance.

Tools Required

  • 5mm Allen wrench
  • Torque wrench
  • T25 Torx wrench
  • Phillips screwdriver
  • B-screw adjustment tool (if necessary)
  • Bike stand
  • Chain checker tool
  • SRAM AXS app (for electronic configuration)

Installation of RED eTap AXS D2 Rear Derailleur

Proper installation is the first step in achieving optimal performance with the RED eTap AXS D2 rear derailleur. Follow these steps to ensure correct installation:

  1. Mount the Rear Derailleur Hanger:
    • Attach the rear derailleur hanger to the frame using the appropriate bolts. Ensure that the hanger is straight and aligned properly.
  2. Attach the Derailleur to the Hanger:
    • Use a 5mm Allen wrench to secure the rear derailleur to the derailleur hanger. Tighten the bolt to the manufacturer’s recommended torque specification to prevent any movement or misalignment.
  3. Install the Chain:
    • Thread the chain through the jockey wheels of the derailleur, ensuring that it follows the proper routing path through the front and rear cogs. The chain should be the correct length for your setup, with no excess slack or tension.
  4. Secure the Rear Derailleur Cables:
    • If you are using a manual configuration with cables, make sure that the cables are properly threaded into the derailleur and that the barrel adjusters are set to an appropriate baseline.
  5. Connect the AXS Battery:
    • Attach the AXS battery to the derailleur by snapping it into place. If the derailleur is wireless, ensure the battery has been charged and properly installed.

Adjusting the RED eTap AXS D2 Rear Derailleur

Once the rear derailleur is installed, it’s essential to fine-tune the adjustments to ensure smooth shifting across all gears. Here’s how you can do that:

Setting the High and Low Limit Screws

The limit screws control how far the derailleur can travel in both the smallest and largest gear combinations. Incorrect setting of the limit screws can result in poor shifting performance or even damage to the drivetrain.

  1. Set the High Limit Screw:
    • Shift to the smallest cog in the rear cassette.
    • Using a T25 Torx wrench, adjust the high limit screw to ensure that the derailleur is positioned correctly and does not over-shift past the smallest cog.
  2. Set the Low Limit Screw:
    • Shift to the largest cog in the rear cassette.
    • Adjust the low limit screw so that the derailleur does not shift past the largest cog, avoiding chain drop or derailleur damage.

B-Screw Adjustment

The B-screw controls the distance between the derailleur’s jockey wheels and the cogs. If the distance is too close, the chain may rub on the derailleur; if it is too far, shifting performance can degrade.

  1. Shift to the largest cog.
  2. Adjust the B-screw with a Phillips screwdriver to ensure that the jockey wheel is positioned approximately 6–8mm away from the largest cog. This is the ideal range for the B-screw adjustment.

Fine-Tuning the Electronic Shifting

Since the RED eTap AXS D2 utilizes electronic shifting, ensuring that the electronic system is properly calibrated is crucial for smooth shifting. To fine-tune the electronic shifting:

  1. Enter the AXS App:
    • Open the SRAM AXS app and connect to the rear derailleur via Bluetooth.
  2. Adjust the Trim:
    • The app will allow you to fine-tune the trim settings for the rear derailleur. This enables small adjustments to ensure smooth shifts and prevent chain rub when shifting across the cassette.
  3. Check Battery and Firmware:
    • Use the app to check that the battery in the derailleur is fully charged and that the firmware is up to date.

Troubleshooting Common Setup Issues

Even after proper installation and adjustments, you may encounter issues with your shifting. Here are some common problems and how to troubleshoot them:

Skipping Gears or Delayed Shifting

  • Potential Cause: The derailleur may not be properly aligned or the high/low limit screws may need further adjustment.
  • Solution: Double-check the alignment of the derailleur hanger and ensure that the limit screws are correctly set. You may also need to check the chain length to ensure it’s properly sized for your drivetrain.

Chain Drop or Jumps Between Gears

  • Potential Cause: The derailleur hanger may be bent, or the B-screw may need adjustment.
  • Solution: Inspect the derailleur hanger for any signs of bending or misalignment. Adjust the B-screw to set the correct jockey wheel distance from the largest cog.

Noisy Shifting or Chain Rubbing

  • Potential Cause: The B-screw adjustment may not be properly set, or the derailleur’s jockey wheels may be dirty.
  • Solution: Clean the jockey wheels and adjust the B-screw to maintain the correct gap between the derailleur and the cogs. Recheck the chain and cassette for wear.

Customization and Optimization for Better Performance

To enhance the performance of your RED eTap AXS D2 rear derailleur, there are a few customization options worth considering:

Optimizing the Chain for Gravel Riding

Gravel bikes often encounter dirt and debris, which can accelerate chain wear. A high-quality, gravel-specific chain with anti-corrosion coating can increase the longevity and performance of your drivetrain.

  • Upgrade Option: Consider using a wider chain with better sealing for gravel conditions to reduce the likelihood of dirt and grime interfering with the shifting.

Fine-Tuning the AXS App for Gravel-Specific Settings

For gravel biking, riders may prefer more aggressive or smoother gear ratios depending on terrain. The SRAM AXS app allows for customization of gear ratios, enabling riders to adjust the trim for smoother shifting across varied terrain.

  • Customization Tip: Set up gear shifts that accommodate the steep and unpredictable nature of gravel riding. Adjust the app settings to allow for quicker shifting in high-torque conditions.

Comparing RED eTap AXS D2 with Other Models

While the RED eTap AXS D2 is designed for top-tier performance, there are other rear derailleurs in SRAM’s lineup that cater to different riding styles. Let’s compare the RED eTap AXS D2 with the Force eTap AXS and Rival eTap AXS derailleurs.

  • Weight and Performance:
    • The RED eTap AXS D2 is the lightest and most performance-focused option, ideal for competitive gravel races and endurance events.
    • The Force eTap AXS offers a slightly heavier option but provides excellent performance at a more affordable price point.
    • The Rival eTap AXS is the most budget-friendly, making it ideal for riders who need dependable shifting without compromising on basic features.
  • Customization and Compatibility:
    • The RED eTap AXS D2 offers the most advanced customization options through the AXS app, which is perfect for cyclists who want to fine-tune every detail.
    • Force and Rival models are slightly less customizable but still provide excellent performance for the majority of gravel riders.

Compatibility with Other Drivetrain Components

The RED eTap AXS D2 rear derailleur is compatible with SRAM’s AXS system, which allows for seamless integration with other AXS components such as chainsets, cassettes, and power meters. However, it’s important to ensure that your cassette, crankset, and chain are all compatible with a 12-speed setup for optimal performance.

  • Rear Cassette Compatibility: The RED eTap AXS D2 is compatible with 12-speed cassettes in a wide range of gear ratios, from the more standard 10-33T to gravel-specific 10-36T or even larger.
  • Chain Compatibility: You will need a 12-speed chain, as the drivetrain is designed for narrow, high-performance chains that minimize friction and improve shifting precision.

By following these steps and recommendations, you can achieve the best performance from your RED eTap AXS D2 rear derailleur, ensuring smooth, efficient shifting for your gravel bike. Proper installation, adjustment, and regular maintenance will keep your drivetrain functioning at its peak for years to come.