Fixing Chain Drops on Gravel Bikes with Force XPLR eTap AXS Rear Derailleurs

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Chain drops can be a frustrating issue for gravel bike riders, especially when you’re pushing through challenging terrain. For riders using the SRAM Force XPLR eTap AXS [paid link] rear derailleur, there are a few specific causes and solutions for preventing chain drops. In this guide, we’ll walk you through the steps for fixing chain drops, troubleshooting common issues, and optimizing your drivetrain setup for smoother rides on gravel.

Understanding Chain Drops on Gravel Bikes

Chain drops typically occur when the chain falls off the front or rear cassette, usually due to improper gear shifts or an ill-adjusted drivetrain. Gravel bikes often experience chain drops more than road bikes because of the rougher terrain, aggressive shifting, and often, more pronounced suspension movements. The Force XPLR eTap AXS derailleur, designed specifically for gravel riding, has features that can minimize chain drop risk, but setup and maintenance are critical to ensuring reliable performance.

Common Causes of Chain Drops

  1. Improper derailleur tension: If the rear derailleur is too loose or tight, it can cause inaccurate shifts, leading to chain drops.
  2. Dirty or worn-out components: A dirty chain, derailleur jockey wheels, or cassette can affect the smoothness of the drivetrain, increasing the chances of the chain falling off.
  3. Incorrect limit screw settings: If the derailleur limit screws are set improperly, the derailleur may overshoot the gears or misalign, leading to chain issues.
  4. Chain length issues: An excessively long or short chain can affect the derailleur’s range and cause misalignment when shifting.
  5. Cassette wear: Worn or damaged cogs in the cassette can also create shifting problems, which might lead to a dropped chain.

Tools Required

  • 5mm Allen wrench
  • Torque wrench
  • Chain checker tool
  • Chain lube
  • Cleaning supplies (brushes, degreaser)
  • New chain (if needed)
  • SRAM AXS app (for eTap setup and configuration)

Installing the Force XPLR eTap AXS Rear Derailleur

Before addressing chain drops, ensuring the derailleur is correctly installed is crucial. Here’s a step-by-step guide for installation:

  1. Remove the old derailleur: Use a 5mm Allen wrench to remove the bolts holding your current derailleur.
  2. Attach the new Force XPLR eTap AXS derailleur: Position the derailleur hanger on the frame and secure the Force XPLR derailleur with the same bolt and a torque wrench to ensure it’s correctly fastened.
  3. Install the chain: Carefully thread the chain through the derailleur’s jockey wheels, making sure the chain is properly threaded.
  4. Check alignment: Make sure the derailleur is aligned parallel to the cassette and doesn’t touch the frame.
  5. Connect the AXS system: Sync the derailleur to your bike’s eTap AXS system using the SRAM AXS app.

Once the derailleur is installed, make sure to double-check all bolts and ensure there’s no excessive play in the system.

Adjusting the Force XPLR eTap AXS Derailleur

Proper adjustment of the rear derailleur will go a long way in preventing chain drops. The Force XPLR eTap AXS system is designed for easy electronic shifting, but it still requires a precise setup to function optimally.

Adjusting Limit Screws

  1. Shift to the smallest cog: Using your eTap shifter, shift the chain to the smallest cog in the rear cassette.
  2. Check the high limit screw: The derailleur should not overshoot into the spokes. Adjust the high limit screw (marked with an “H”) to stop the derailleur from moving too far inward.
  3. Shift to the largest cog: Shift to the largest cog in the rear cassette.
  4. Check the low limit screw: Ensure that the derailleur doesn’t shift off the outermost cog. Adjust the low limit screw (marked with an “L”) to ensure proper positioning.

Fine-Tuning B-Screw Adjustment

The B-screw controls the distance between the derailleur jockey wheels and the cassette. A correctly adjusted B-screw ensures smooth shifting, reducing the chances of the chain dropping.

  1. Shift to the largest cog: Again, shift to the largest cog in the rear cassette.
  2. Adjust the B-screw: The gap between the jockey wheel and the cassette should be around 5-6mm. Adjust the B-screw accordingly to ensure optimal clearance.

Preventing Chain Drops

1. Regular Cleaning and Lubing

A clean drivetrain is key to preventing chain drops. Dirt, grit [paid link], and debris can cause the derailleur to misalign or cause the chain to slip off. Regularly clean your chain, cassette, and derailleur with degreaser and lubricate the chain after cleaning.

  • Clean the drivetrain: Use a degreaser and a stiff brush to scrub the chain, cassette, and derailleur.
  • Lubricate the chain: Apply a small amount of chain lube, then wipe off excess to prevent dirt buildup.

2. Chain Length and Tension

Having the correct chain length is essential for smooth shifting. If the chain is too long or too short, the derailleur may not be able to properly engage the gears, leading to chain drops.

  • Measure chain length: Use a chain checker tool to ensure the correct chain length.
  • Check derailleur tension: If the derailleur cage tension feels too slack or too tight, adjust it using the barrel adjuster on the derailleur.

3. Check for Worn Components

Over time, components like the chain and cassette will wear out, increasing the likelihood of chain drops. Replace the chain regularly and inspect the cassette for wear.

  • Replace the chain: If the chain checker tool indicates wear, replace the chain to maintain smooth shifting.
  • Inspect the cassette: Check for worn teeth or a worn-out cassette. Replace it if necessary.

4. Fine-Tune Shifting Performance

The Force XPLR eTap AXS derailleur has electronic shifting, which allows for precise adjustments via the SRAM AXS app. If chain drops continue, use the app to check for any system errors and fine-tune the shifting performance.

  • Run a diagnostic: Use the SRAM AXS app to check the status of the derailleur and make adjustments to the electronic shift settings.
  • Adjust the trim: If you notice shifting issues, try adjusting the trim using the app to optimize performance.

Troubleshooting Common Chain Drop Issues

Despite proper setup, chain drops can still occur due to factors like misalignment, component wear, or issues with the electronic system. Here are some troubleshooting steps to help you fix common problems:

Chain Drops During Shifting

  • Check derailleur alignment: Ensure the derailleur is not bent or misaligned. A misaligned derailleur may struggle to shift properly, leading to chain drops.
  • Inspect your shifter: Ensure the eTap shifter is working correctly. A malfunctioning shifter can send incorrect signals to the derailleur, causing the chain to drop.

Chain Drops at Low Gears

  • Increase derailleur tension: If the chain drops while in the lowest gears, the derailleur may not have enough tension. Adjust the derailleur tension to keep the chain in place.
  • Check the B-screw setting: If the gap between the derailleur and the cassette is too large, it can cause chain drops, especially in low gears. Adjust the B-screw to reduce the gap.

Chain Drops at High Gears

  • Check the high limit screw: If the chain is dropping in the higher gears, the derailleur may be overshooting the cassette. Ensure the high limit screw is properly adjusted to prevent this.

Comparing the Force XPLR eTap AXS to Other Gravel Drivetrain Options

While the SRAM Force XPLR eTap AXS rear derailleur is specifically designed for gravel bikes, it’s important to understand how it compares to other popular models in the gravel market, such as Shimano GRX and Campagnolo Ekar.

  • SRAM Force XPLR eTap AXS: Offers wireless shifting, a wide gear range, and precise performance for gravel and mixed-terrain riding. Its electronic system allows for fast, accurate shifting with minimal maintenance.
  • Shimano GRX: Known for its mechanical shifting reliability, the GRX groupset is a solid option for riders who prefer traditional shifting. It offers robust performance but lacks the electronic ease of the Force XPLR.
  • Campagnolo Ekar: A 13-speed gravel-specific drivetrain that offers a unique gear range for off-road riders, but with fewer customization options compared to SRAM’s eTap AXS system.

The Force XPLR eTap AXS stands out for its electronic shifting and ease of customization through the AXS app, making it a top choice for tech-savvy gravel riders.

Conclusion

Fixing chain drops on your gravel bike with the SRAM Force XPLR eTap AXS rear derailleur requires proper installation, adjustment, and regular maintenance. By ensuring your derailleur is correctly aligned, maintaining a clean drivetrain, and fine-tuning your shifting, you can minimize the risk of chain drops and improve your overall riding experience. Regular checks and adjustments will keep your drivetrain functioning smoothly, allowing you to focus on your gravel adventures without the worry of dropped chains.