Replacing the cable on your Campagnolo Chorus 12s [paid link] front derailleur is an essential part of drivetrain maintenance that ensures smooth, accurate, and responsive shifting. Over time, derailleur cables stretch, fray, or accumulate dirt, which can reduce performance and compromise reliability. This guide provides a complete, step-by-step process for replacing the cable, along with adjustment techniques and expert tips for keeping your Chorus 12s [paid link] front derailleur performing like new.
Tools Required
- 4 mm and 5 mm hex keys [paid link]
- Cable cutters
- Torque wrench [paid link] (Nm scale)
- Campagnolo-approved derailleur cable and housing
- Pick tool or awl (for lining up housing ends)
- Light grease or assembly paste
Preparing the Bike for Cable Replacement
Before beginning, shift the chain onto the small chainring and the middle of the cassette. This position reduces tension on the cable and makes the derailleur easier to work with. Inspect the existing cable routing carefully, noting the direction and housing length. Campagnolo Chorus 12s [paid link] is sensitive to precise routing, so replacing the cable exactly as installed is critical to achieving optimal shifting.
Remove the handlebar tape only as much as needed to access the cable entry point at the shifter. If the tape is worn, consider replacing it during this procedure.
Removing the Old Cable
Loosen the cable anchor bolt on the derailleur with a 5 mm hex key. Once the bolt is free, pull the cable housing away from the derailleur stop and slide the cable out completely. If the cable end is frayed or stuck, use cutters to trim the tip and pull it cleanly.
At the shifter, release the brake hood and locate the cable head. Gently push the old cable through the shifter mechanism until it slides out. Do not force the cable, as this can damage the internal routing of the Campagnolo Ergopower lever.
Installing the New Cable
Lightly grease the new cable before threading it through the shifter. Insert the cable head into the designated cradle of the Ergopower lever and feed it through the internal guide. Ensure it exits cleanly and aligns with the existing housing.
Check that the housing ends are properly cut, square, and fitted with ferrules. Use a pick tool to open any compressed housing liner before inserting the cable. This ensures minimal friction and smoother shifting.
Feed the cable through the derailleur stop and under the anchor plate. Pull it taut and position it correctly before tightening the anchor bolt to the manufacturer’s specified torque of 5–7 Nm.
Adjusting Tension and Limits
After securing the cable, fine-tune the derailleur. Use the barrel adjuster to set the proper cable tension. The front derailleur of the Chorus 12s requires precise adjustment because of the narrow spacing of the 12-speed chainrings. Too little tension can cause delayed upshifts, while too much can create chain rub or overshifting.
Check the limit screws. The low limit should allow smooth movement onto the small chainring without rubbing, while the high limit should position the derailleur cage just outside the large chainring teeth. Campagnolo’s tolerance is tight, so small adjustments often make a big difference.
Testing the Shifting
Once adjusted, shift repeatedly between the small and large chainrings under light pedaling force. The derailleur should move crisply, without hesitation or grinding noises. Watch for chain rub on both the inside and outside of the cage when cross-chaining, as this may indicate improper cable tension or limit screw settings.
Re-wrap the handlebar tape securely and double-check all fasteners with a torque wrench [paid link]. A loose anchor bolt or improperly tightened housing stop can quickly degrade shifting performance.
Troubleshooting Common Issues
If the derailleur hesitates when shifting up to the big chainring, the cable may not have been pre-stretched. To fix this, pull firmly on the exposed section of the cable near the derailleur, then re-tighten the anchor bolt.
If shifting feels sticky or inconsistent, inspect the housing for kinks or dirt. Campagnolo drivetrains rely on low-friction cable systems, so even slight contamination can compromise performance. Replace any worn housing sections immediately.
If noise persists after adjustment, verify derailleur alignment with the chainrings. The cage must run parallel to the chainrings for optimal performance.
Extending Cable Lifespan
To maximize the lifespan of your new cable, clean and lubricate it periodically, especially after wet or dusty rides. Avoid excess lubrication, as this can attract grit. Replace cables at least once per season if you ride frequently, or more often if you notice any reduction in shifting accuracy.
By following these steps, you can replace the cable on your Campagnolo Chorus 12s front derailleur with precision, restoring crisp and reliable front shifting. Proper installation and adjustment ensure that your drivetrain runs efficiently, allowing you to enjoy smooth performance for many miles.