6 speed shifter, 7 speed cassette?

philcubed
philcubed Posts: 260
edited August 2019 in MTB workshop & tech
Hi, I'm sorting my daughters uni bike ready for the new term. Just a cheap thing.
The back wheel got kicked in last year, so I was going to replace it with a spare wheel I have.
Trouble is, the old wheel/ shifter is 6 speed (freewheel), the spare wheel is 7 speed (freehub). Will I be able to set up to use 6 gears on the 7 speed cassette with the current shifter, or is the cable pull different between 6 and 7 gear?
Otherwise, I'll get a 7 speed shifter.
Cheers

Comments

  • PhilipPirrip
    PhilipPirrip Posts: 616
    No harm in giving it a go. With older Shimano stuff we used to mix and match components of different speeds without probems.

    Drop the chain onto the 7th sprocket with the lever in 6th gear, tension the cable and tighten the bolt and use the cable adjusters to line everything up then go up the block and see if all the other gears index cleanly.

    If they do then just set the limiting screws accordingly, if they don't work then get the 7 speed shifter.
  • cycleclinic
    cycleclinic Posts: 6,865
    The spacing different for 6 and 7 speed so some mistake shifting will result but it will work.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • steve_sordy
    steve_sordy Posts: 2,453
    There is little worse than poor shifting to suck the joy out of a bike. Do it right, it will be cheap to do.

    Google 7-speed shifter right hand and see what you get.
    I got this Shimano Altus 7-speed shifer for ££8.95

    https://www.amazon.co.uk/Shimano-Respon ... th=1&psc=1

    All you have to be sure of is that the shifter and mech match by brand, normally if it's not Shimano, then it's SRAM
    This one for example at £9.99
    https://www.bikester.co.uk/bike-parts/g ... v_chn=shop

    Don't take my word for it do your own checking and shopping!
  • The Rookie
    The Rookie Posts: 27,812
    As above, the sprocket spacing on 6 speed is 5.5mm, on 7 speed its 5.0mm, so over five clicks (from high to low) you'll have a 2.5mm error, or half a gear space, the chance of making it work decently are very remote.

    A 7 speed shifter will work just fine with your 6 speed mech, so you only need a new (or new to you) shifter.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • philcubed
    philcubed Posts: 260
    OK Cheers. I'll get a shifter then. Thanks for the advice.

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