DIY Guide to Replacing Derailleur Cables for RED eTap AXS (12-speed)

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Replacing the derailleur cables on your SRAM RED eTap AXS (12-speed) is an essential maintenance task that ensures smooth shifting performance. Whether you’re upgrading your components or troubleshooting shifting issues, this guide will provide you with all the information you need for a successful replacement.

Tools Required

  • 5mm Allen wrench
  • Flathead screwdriver
  • Torque wrench
  • Diagonal cutting pliers
  • Cable cutters
  • Lubricant (bike-specific)
  • Cable housing
  • New derailleur cables
  • Cable crimps (if necessary)
  • Cleaning brush
  • Rag for cleaning

Preparing for the Cable Replacement

Before starting the cable replacement process, make sure your bike is stable. Use a work stand or position your bike upside down, ensuring it’s secure. Make sure the rear derailleur is in the smallest cog to relieve tension on the cable.

Step 1: Remove the Existing Cables

  1. Remove the battery: Since the RED eTap AXS system is wireless, the first step is to remove the battery from the rear derailleur.
  2. Unclamp the derailleur: Using a 5mm Allen wrench, loosen the bolt that attaches the derailleur to the frame. This allows you to pull the derailleur off the hanger for easier access.
  3. Cut the cables: Using your cable cutters, cut the derailleur cables at the entry point of the shifter and at the derailleur. Take care not to damage the housing or derailleur when cutting the cables.
  4. Remove cable housing: Pull the old housing out from the bike frame, starting from the shifter and moving toward the derailleur.

Step 2: Prepare the New Cables

  1. Measure the new cables: Measure the length of the new cables by comparing them with the old ones or by laying them along the frame.
  2. Lubricate the cables: Apply a small amount of bike-specific lubricant to the new cables. This ensures smoother operation and reduces friction over time.

Step 3: Install the New Cables

  1. Install the cable housing: Start by inserting the new cable housing into the frame. Ensure the housing is seated correctly, extending from the shifter to the derailleur.
  2. Thread the cables through the shifter: Insert the new cables into the shifters, ensuring that they pass through the cable entry point without kinks or twists. Make sure the cables are routed smoothly and securely.
  3. Route the cables to the derailleur: Carefully route the cables through the housing, ensuring they follow the correct path towards the derailleur. Make sure to avoid any sharp bends that could lead to shifting issues.
  4. Install the derailleur cable into the derailleur: Insert the cable into the derailleur’s cable anchor bolt, tightening it securely with the Allen wrench. Be sure to leave enough slack in the cable to allow for smooth shifting.

Step 4: Adjust the Tension

  1. Adjust the shifter: Engage the shifter and check the cable tension. It should be tight but not overly stretched. Use the barrel adjuster at the shifter or derailleur to fine-tune the tension. If the shifting feels sluggish or erratic, fine-tune the tension gradually until you get crisp shifts.
  2. Check the derailleur movement: With the cables connected, test the derailleur by manually shifting through the gears. Ensure the derailleur moves smoothly across the cassette and that there is no skipping or hesitation.
  3. Check for proper indexing: Shift through all the gears, checking that the derailleur shifts smoothly across the cassette. If there’s hesitation or misalignment, make micro-adjustments using the barrel adjuster.

Step 5: Secure and Trim the Cables

  1. Crimp the cables: Once the cable is properly tensioned and adjusted, trim any excess cable using your cable cutters. If needed, use a cable crimp to secure the end of the cable to prevent fraying.
  2. Reinstall the derailleur: Reattach the derailleur to the frame, ensuring the bolt is properly torqued. You can refer to your bike manufacturer’s torque specifications for the correct torque setting.
  3. Test the shifting: Perform a final test by shifting through all the gears under load. Ensure that shifting is responsive and smooth.

Troubleshooting Common Set-Up Issues

Even after replacing the cables, you might face some common shifting issues. Here’s how to handle them:

  • Skipping Gears: If your bike skips gears, the derailleur might not be properly indexed. Adjust the barrel adjuster slightly to fine-tune the tension.
  • Sluggish Shifting: This issue could be due to excessive friction in the cables or misaligned cable housing. Check the housing for kinks or bends and replace it if necessary.
  • No Shifting in Certain Gears: This could indicate that the derailleur hanger is bent, causing the derailleur to misalign. You may need to straighten the hanger or replace it.

Customizing and Optimizing for Performance

While replacing the cables, consider the following options to optimize your shifting performance:

  • Use high-quality cable housing: Opt for a premium housing that reduces friction for smoother shifting.
  • Upgrade to stainless steel cables: Stainless steel cables are more durable and provide better performance over time compared to standard steel cables.
  • Check chainline alignment: Ensure your cassette and chainring are aligned to prevent uneven wear and reduce shifting issues.
  • Replace the jockey wheels: Over time, the jockey wheels in the derailleur can wear down, which negatively impacts shifting. Consider upgrading to ceramic jockey wheels for smoother performance.

Comparing with Other Models

The SRAM RED eTap AXS 12-speed drivetrain stands out from other drivetrains, such as Shimano’s Di2 or Campagnolo’s EPS, due to its wireless functionality and intuitive shifting experience. The eTap AXS system offers:

  • Simpler setup: No wires means fewer installation steps and less maintenance complexity compared to Di2 or EPS systems.
  • Customizability: eTap AXS allows for easy adjustments via AXS app, letting you tweak shifting preferences and configurations without tools.
  • Battery life: The RED eTap AXS offers impressive battery life, lasting up to 1,000 miles on a full charge. This compares favorably to its competitors, like Di2, which requires more frequent charging.

Understanding Compatibility

The RED eTap AXS 12-speed is compatible with SRAM’s AXS components, meaning it pairs well with AXS chainsets, cassettes, and chainrings. However, it is not directly compatible with Shimano or Campagnolo components. When replacing or upgrading your drivetrain, it’s essential to ensure that your components are AXS-compatible to avoid shifting issues.

The eTap AXS system is also backward compatible with 11-speed cassettes, making it versatile if you’re looking to switch to a higher-end system. However, it’s important to note that the performance may not be optimal if paired with components outside the SRAM AXS family.

By following this guide, you can confidently replace your derailleur cables, ensuring your SRAM RED eTap AXS (12-speed) drivetrain is working at its best, providing smooth, reliable shifting performance for your rides.