Okay, here is how to remove a rear derailleur from a bike.
Removing a rear derailleur typically involves disconnecting the shift cable, managing the bicycle chain, and unbolting the derailleur itself from the frame's derailleur hanger.
How to Remove a Rear Derailleur from a Bike
Removing your rear derailleur is a common maintenance task, necessary for cleaning, replacement, or other bike repairs. It requires a few basic tools and careful handling of the bike's shifting and drivetrain components.
Tools You'll Need
- Allen keys (commonly 5mm, but check your derailleur's specific bolt size)
- Cable cutters (optional, if you need to cut the cable)
- Chain tool or master link pliers (if you plan to open the chain)
Step-by-Step Guide
Here's a breakdown of the process:
- Shift to the Smallest Cog: Before you begin, shift your rear derailleur so the chain is on the smallest cog on the cassette. This releases tension on the shift cable, making it easier to work with.
- Release Cable Tension: Locate the cable anchor bolt on the rear derailleur. Use the appropriate Allen key to loosen this bolt. This allows the shift cable to become slack and detach from the derailleur's pull mechanism.
- Disconnect the Shift Cable: Once the cable anchor bolt is loose, you can pull the end of the shift cable free from the derailleur. Some derailleurs have a small cap on the cable end which you might need to remove first. Carefully thread the cable out of any guides on the derailleur body.
- Address the Bicycle Chain: The chain passes through the derailleur's jockey wheels. You have a couple of options here:
- Option A (Common): Open the chain using a chain tool (for chains without a master link) or master link pliers (if your chain has a master link). This completely separates the chain, making derailleur removal and reinstallation cleaner.
- Option B (Let it Hang): If you choose not to fully open the chain, or if the chain remains attached to the chainrings and cassette, the chain will need to be guided out of the derailleur pulleys as you remove it. As mentioned in the reference, "If the chain and cable were left attached. Simply allow it to hang" after the derailleur is unbolted. This means if the cable isn't fully free or the chain is still looped through, the components will dangle once the derailleur body is detached from the frame.
- Unbolt the Derailleur: The rear derailleur is attached to the frame via the derailleur hanger (which is either integrated into the frame or a separate replaceable part) using a large bolt, often called the B-pivot bolt. This bolt typically requires a 5mm or 6mm Allen key. Support the weight of the derailleur and use the Allen key to unscrew this bolt counter-clockwise.
- Remove the Derailleur: Once the B-pivot bolt is completely removed, the rear derailleur is free from the bike. Carefully take it away, being mindful of the chain (if still attached) and the loose shift cable.
- Check the Hanger: With the derailleur removed, this is a good time to inspect the derailleur hanger. "The Hanger can now be checked for alignment." A bent hanger is a common cause of poor shifting, so verifying it is straight is a crucial step before installing a new or the old derailleur.
Summary Table
| Step | Action | Notes |
|---|---|---|
| 1. Prepare | Shift to the smallest rear cog. | Reduces cable tension. |
| 2. Release Cable | Loosen the cable anchor bolt. | Frees the shift cable end. |
| 3. Disconnect Cable | Pull the shift cable free from the derailleur. | Ensure it's clear of derailleur guides. |
| 4. Handle Chain | Open chain (tool/pliers) OR guide out as derailleur is removed. | "If the chain and cable were left attached. Simply allow it to hang" |
| 5. Unbolt Derailleur | Unscrew the B-pivot bolt attaching derailleur to the hanger (e.g., 5mm Allen). | Support the derailleur's weight. |
| 6. Remove Derailleur | Carefully take the derailleur away from the bike. | Mind the chain and cable. |
| 7. Inspect Hanger | Check the derailleur hanger for straightness. | "The Hanger can now be checked for alignment." |
By following these steps, you can safely and effectively remove your rear derailleur for maintenance or replacement.
