Help with gears, cassette and shifter.

Hi guys I have recently acquired a Claude butler mountain bike which has 9 rear sprockets, I needed a new derailleur so I bought a Shimano Deore M610 10 Speed rear mech, the bike has a gear shifter for only 7, so I’ve set the derailleur to the 7 I gears I want for now. My question is can I use a 10 speed shifter on my current configuration and would the shifter need to be shimano.? Even thought the derailleur is 10 speed the cassette is only 9 so I use the limit screws to restrict it to 9, would a 10 speed shifter cause me an issue. Hope this makes sense.

Thanks guys


  • whyamihere
    whyamihere Posts: 7,686
    It won't work. I'm surprised you have it shifting 7 gears because the pull ratios are different.

    If you want to use 9 sprockets, then you need a 9 speed shifter and a 9 speed mech, and they need to be from the same manufacturer (though there is limited compatibility for specific parts between manufacturers). The spacing between cogs is different between 9 speed and 10 speed cassettes, meaning a 10 speed mech and shifter will undershoot compared to a 9 speed system. Also, Shimano changed the pull ratio (the distance the mech moves per click of the shifter) for 10 speed MTB parts, so even trying to pair a 9 speed shifter with your 10 speed mech won't work properly. These issues compound the more gears you try to shift across, so you may get a few working, but you won't get 9 gears all working correctly.
  • Thanks for the reply.
  • gbsahne001
    gbsahne001 Posts: 1,973
    Not entirely correct; you can use a 7 / 8 / 9 speed rear mech and a 9 speed shifter with very little problem. The chain size is also almost identical and pull ratios are compatible.

    The problem comes on the 10 speed drivetrain, as 10 speed requires a 10 speed cassette / shifter and rear mech as these are incompatible with other flavours of drivetrain, which is why it doesn't work so well with the 9 speed you're trying to use it with.