How to Adjust Your Rear Derailleur for an Index Shifter

If your have problems with your chain jumping between rear cogs, it is likely that your rear derailleur needs adjustment. However, getting a rear derailleur adjusted to shift correctly with an index shifter can be a challenge. Fortunately, there is a trick to adjust it right on the first try.

Difficulty: Moderate

Instructions

Things You'll Need:

• 9 mm open-end or socket wrench
• Hex wrenches
• 4th hand tool

1. Use a wrench to loosen the nut holding the shift cable. The rear derailleur should swing towards your smallest cog (highest gear). Turn the pedals to make sure this happens. If it doesn't happen, you need to lube the joints of the derailleur cage so it swings freely.

2. Shift to the smallest chain ring in the front.

3. Use your finger to push the derailleur cage to the low gear (largest cog) in the rear, while you use your other hand to pedal. Once you hit the largest cog, stop pedaling and do the adjustment. The cage should be clear of the chain but not be able to go higher and shift the chain into your spokes. The L(ow gear) screw is adjusted to prevent this. If you look into insides of the derailleur, it will be clear which screw you need to turn.

4. Turn the cable tension barrel adjuster, that is, the barrel sitting right at the ferrule that caps the cable housing, so it is half way out. This step is not strictly necessary, but it will be helpful for making small adjustments later on.

5. Shift to the largest chain ring in the front.

6. Move the chain to the second smallest cog using the method described in step 3. Move the index shifter to the second highest gear.

7. Use the 4th hand tool to adjust the gear cable so that the derailleur cage tracks correctly on the second highest gear / second smallest cog. Tighten the nut holding the gear cable. The index system should now be adjusted correctly.

8. Shift to your highest gear / smallest cog and adjust the H(igh gear) screw to prevent the chain from being throw off.