The Campagnolo Chorus 12-speed rear derailleur is a high-performance component designed for smooth, precise shifting on the road. Over time, the derailleur cables can become frayed or worn, which may lead to poor shifting performance. Replacing the derailleur cables is a crucial maintenance task to ensure your bike continues to perform at its best. This guide will walk you through the process of replacing the derailleur cables on a Campagnolo Chorus 12-speed rear derailleur.
Tools Required
- New derailleur cables (Campagnolo-specific for optimal performance)
- 5mm Allen wrench
- Cable cutters
- Torque wrench
- Flathead screwdriver
- 2mm Allen wrench
- Lubricant (preferably bike-specific grease or cable lube)
- Cloth for cleaning
- Bike stand (optional but recommended)
Preparation: Setting Up Your Bike
Before starting, make sure your bike is properly secured. If possible, mount your bike on a bike stand for stability. If you do not have a bike stand, flipping the bike upside down is a feasible alternative. Here are a few initial steps to ensure a smooth replacement process:
- Shift the bike into the smallest cog on the rear cassette to relieve tension on the derailleur cables.
- Remove any accessories or items that may obstruct access to the derailleur, such as panniers or reflectors.
- Ensure the chain is clean and free of debris.
Step 1: Remove the Old Cables
Disconnect the Rear Derailleur from the Shifter
To start the process, you need to disconnect the derailleur cables from both the rear derailleur and the shifter. Here are the steps:
- Rear Derailleur: Use a 5mm Allen wrench to unscrew the bolt holding the derailleur cable in place on the derailleur. Carefully remove the cable from the derailleur.
- Shifter: Shift the bike into the smallest cog, then use a 2mm Allen wrench to remove the bolt securing the cable to the shifter.
Remove the Cable Housing
After disconnecting the cable, carefully pull out the cable housing from both the derailleur and the shifter. Take care not to damage the cable housing, as it may be reused if still in good condition. If the housing is worn or damaged, replace it.
Step 2: Install the New Derailleur Cable
Lubricate the New Cable
Before installing the new derailleur cable, it’s important to lubricate it lightly. This will help reduce friction and ensure smooth shifting. Apply a thin layer of lubricant to the entire length of the cable, making sure it’s evenly distributed.
Insert the New Cable into the Shifter
Feed the new cable into the shifter, starting from the housing entry point. Push the cable through until it exits at the cable exit port. Secure the cable temporarily with your fingers or a cloth to avoid it slipping out.
Insert the Cable into the Derailleur Housing
Feed the cable through the derailleur housing and insert the housing into the appropriate entry and exit points on the frame and derailleur. Ensure that the housing is snugly fitted and that no kinks are present, as this could impede shifting.
Step 3: Attach the Cable to the Rear Derailleur
- Thread the Cable: Push the new cable through the entry port of the rear derailleur.
- Tighten the Bolt: Use a 5mm Allen wrench to tighten the bolt that secures the derailleur cable. Be careful not to overtighten, as excessive force can damage the derailleur.
Step 4: Adjust the Cable Tension
Once the cable is secured to the derailleur, you’ll need to adjust the cable tension for optimal shifting performance. Here’s how to do it:
- Shift the Gears: Shift your bike to the middle cog of the cassette to make the adjustments easier.
- Adjust Using the Barrel Adjuster: Use the barrel adjuster on the derailleur or shifter to fine-tune the tension. Turn it clockwise to increase tension and counterclockwise to decrease tension. You want the derailleur to shift smoothly through the gears without hesitation.
- Test the Shifting: Shift through all the gears, making sure the derailleur moves freely between cogs. If the shifting is sluggish or skips gears, adjust the cable tension accordingly.
Step 5: Final Check and Fine-Tuning
Once you’ve installed and adjusted the new cables, perform the following checks:
- Check for Cable Slack: Ensure that the derailleur is not hanging loosely, and that there is no excess slack in the cable.
- Test Under Load: Spin the pedals while shifting through the gears to ensure the derailleur operates smoothly under load.
- Check the Limit Screws: Adjust the high and low limit screws on the derailleur to prevent the chain from shifting beyond the cassette range.
Step 6: Trim the Cable
After ensuring the derailleur is shifting smoothly, trim any excess cable. Use cable cutters to carefully cut the cable just beyond the derailleur. Add a cable end cap to prevent the cable from fraying and ensure a clean, professional finish.
Troubleshooting Common Issues
Even with the proper installation, issues may arise. Here are some common problems and their solutions:
- Poor Shifting or Hesitation: This could be due to incorrect cable tension. Try adjusting the barrel adjuster to either tighten or loosen the cable slightly.
- Skipping Gears: Skipping gears can happen if the cable is too loose or if the derailleur hanger is bent. Recheck cable tension and ensure the derailleur hanger is aligned correctly.
- Difficulty Shifting: This can be caused by dirty or worn-out cable housing. Clean the housing thoroughly or replace it if necessary.
Conclusion
Replacing the derailleur cables on a Campagnolo Chorus 12-speed rear derailleur is an essential maintenance task that can significantly improve shifting performance. By following the steps outlined above, you can ensure smooth, precise shifting and extend the lifespan of your drivetrain components. Regular cable maintenance, along with proper lubrication and adjustments, will keep your bike operating at its best for years to come.