Adjusting rear derailleur
Adjusting rear derailleur
Adjusting rear derailleur on a bicycle requires very subtle adjustments to correct indexing. It is imperative that you do this properly to ensure the correct function of the bicycle drivetrain.
The prerequisite to a successful adjustment is confirming:
- the derailleur hanger is straight and has not been damaged
- the derailleur itself has not be damaged and is properly aligned withe the frame.
- Clockwise turns loosen the cable causing the derailleur to move down the cassette to larger ratios
- Counterclockwise turns tighten the cable causing the derailleur to move up the cassette to smaller ratios.
If either of the prerequisites are true, make sure they are corrected prior to attempting the adjustment.
No amount of adjustment can compensate for an improperly aligned frame or rear derailleur.
The basic adjustment norms are:
- Use the fourth cog from the left to set the indexing
- make adjustments in very small incremental or decremental turns of the barrel
- adjust to where the shift coincides with the movement of the chain
- keep the chain turning while shifting to verify the adjustment
- Adjust to eliminate all in between gear chain noises
