How to Use a 9 Speed Rear Derailleur on a 10 Speed Cassette

The latest innovation in racing bike gears is the introduction of 10- and even 11-speed rear gears. It is possible to upgrade to a 10-speed cassette without replacing your original nine-speed rear derailleur.

Instructions

  1. Check Component Compatibility

    • 1

      Check the compatibility of your nine-speed rear derailleur with your 10-speed cassette. The cassette and rear derailleur should be made by the same manufacturer to ensure smooth and accurate shifting, for example Shimano cassettes work best with Shimano rear derailleurs.

    • 2

      Ensure that the shifters are 10-speed and the same make and model as the cassette. This is crucial as the indexing of the shifters -- the amount of cable pulled by each click -- must match the spacing between each sprocket of the cassette.

    • 3

      Install a 10-speed chain. Ten-speed chains are narrower than nine-speed chains so they match the narrower spacing between the sprockets on the cassette. Place the chain over the jockey wheels of the rear derailleur to ensure the narrower chain matches the teeth of the cogs.

    • 4

      Install and set up the gears as usual. Before riding, check the gears shift up and down the cassette without double shifting or slipping and that the chain runs smoothly through the drivetrain.