How to Replace a Derailleur Hanger

The derailleur hanger may look insignificant. However, this finger-size piece of metal does more than connect the derailleur to the bicycle frame; a properly aligned hanger is critical to smooth shifting. A crash or other accident can cause the hanger to bend, causing inaccurate transfer of the chain to the rear cogs. Installing a new hanger restores accuracy of shifting.

Things You'll Need

  • 5mm hex key
  • 3mm or 4mm hex key
  • Bicycle grease
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Instructions

  1. Derailleur Hanger Removal

    • 1

      Insert a 5mm hex key into the derailleur mounting bolt. Rotate the key left to loosen the bolt.

    • 2

      Separate the derailleur from the hanger. The derailleur will still be attached to the chain. The derailleur and chain do not need to be separated for this procedure.

    • 3

      Note the position of the current derailleur hanger on the bike. The replacement derailleur hanger, once installed, should match the position of the current derailleur hanger.

    • 4

      Use a 3mm or 4mm hex key, depending on the individual derailleur hanger, to loosen the bolts attaching the derailleur hanger to the bicycle frame. Separate the hanger from the bicycle.

    Derailleur Hanger Installation

    • 5

      Apply grease to the derailleur hanger bolt threads.

    • 6

      Attach the replacement derailleur hanger to the bicycle, replicating the position of the former hanger.

    • 7

      Thread the first bolt into the side of the derailleur hanger. Use the proper hex key to tighten the bolt. Repeat for each bolt.

    • 8

      Reattach the derailleur to the side of the bicycle. Use the 5mm hex key to to tighten the bolt.