How to Install Braze on Derailleur

Where some derailleurs use a clamp to secure the derailleur to the bicycle frame, others employ a braze-on -- a bracket welded to the frame to which the derailleur attaches. Proper installation of the derailleur requires precise height and angle adjustments. These adjustments ensure that the derailleur, once tuned, shifts the drive chain effectively.

Things You'll Need

  • Phillips screwdriver
  • Five mm hexagonal wrench
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Instructions

    • 1

      Note the cage on the side of the derailleur. A screw joins the two plates that comprise the cage. Use a Phillips screwdriver to remove the screw.

    • 2

      Remove the clamp bolt from the front of the braze-on derailleur. The bolt requires a five mm hexagonal wrench. Place the bolt and its washer aside.

    • 3

      Fit the cage plates around the chain on the side of the bicycle. Reinstall the screw that joins the plates. Tighten the screw.

    • 4

      Fit the front of the derailleur against the back of the brazed-on bracket. A slot in the bracket accommodates the five mm hexagonal bolt.

    • 5

      Hold the derailleur against the brazed-on bracket. Place the washer against the front of the bracket and thread the five mm bolt through the washer and into the derailleur.

    • 6

      Use the five mm hexagonal wrench to tighten the bolt. Tighten the bolt just enough to hold the derailleur in place.

    • 7

      Push the cage at the side of the derailleur out over the largest chain ring. The largest chain ring is the largest gear, mounted to the side of the bicycle.

    • 8

      Check the clearance of the cage from the top of the chain ring. Allow for a clearance of one to three mm. If necessary, loosen the derailleur clamp bolt and slide the derailleur up or down as needed. Tighten the bolt once again.

    • 9

      Push the derailleur cage out over the largest chain ring once again. Standing above the derailleur, note the angle of the outer plate of the cage to the chain ring. The outer plate should be parallel to the chain ring. If necessary, loosen the clamp bolt once again and adjust the angle of the derailleur accordingly.