Can you fit an expander to a 9 speed set up?

Alan P
Alan P Posts: 127
edited November 2014 in MTB workshop & tech
A pal of mine has a 2010 Scott Genius with a 3 x 9 speed set up (QR9 axle) with an 11/34 cassette and wants to go for a 1x9 or even better, 1x10 set up (preferably a 32 at the front). However, does anybody know if he can fit an expander ring (40T) to a 9 speed cassette, either keeping it 9 speed (so dropping a cog somewhere) or adding to make it 10 speed?

Cheers
Ibis Mojo HDR (2014)
Canyon Grand Canyon AL29 (2013)

Comments

  • The Rookie
    The Rookie Posts: 27,812
    If he fits one of the expanders that is just a single sprocket, I see no major issue with it, though he'll have a bigger ratio drop (to 34) than you get with 10 speed (to 36). He may need a really thin spacer to get the gap to the first sprocket of the rest of the cassette right, but probably not, also a 9 speed mech with it's lower largest sprocket capability may suffer......really only one way to find out, but for the cost I'd go 1x10 with conventional parts first.
    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.
  • benpinnick
    benpinnick Posts: 4,148
    As above watch out for spacing issues. The cassette might not bind properly as 8x9spd cogs plus the 10 won't be as wide as 9x9
    A Flock of Birds
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  • jimothy78
    jimothy78 Posts: 1,407
    benpinnick wrote:
    As above watch out for spacing issues. The cassette might not bind properly as 8x9spd cogs plus the 10 won't be as wide as 9x9

    This is true, but if my maths is good, the difference between the two is only 1.11% of the total (normal) width, which equates to about 0.4mm. Unless the existing setup is running at a tiny amount of tolerance, it should be ok.
  • FishFish
    FishFish Posts: 2,152
    Check the cage size too for confirmation ist can cope with the expanded caseette.
    ...take your pickelf on your holibobs.... :D

    jeez :roll:
  • in the last edition of Cycle mag from ctc there was a guy who exp[lained what he did to go 1x9 with a range expander cog fitted, can't remember of the top of my head which of the smaller cogs he lost(7th or 8th gear) to allow for the larger cog, sure there was a spacer mentioned too and a Longer b screw, but sadly the mag went out in the recycling last week,
    i've been contemplating it somewhat,
    Timmo.
    After all, I am Cornish!
    http://cornwallmtb.kk5.org/
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  • Alan P
    Alan P Posts: 127
    Ok, thanks guys. So it's a case of go for a 10spd cassette 11/36 and maybe try that first, then if that's ok then as long as the mech can be adjusted (presumably the B screw), then a 40t expander should be good too (presumably removing the 17t cog) :)
    Ibis Mojo HDR (2014)
    Canyon Grand Canyon AL29 (2013)
  • jimothy78
    jimothy78 Posts: 1,407
    Alan P wrote:
    Ok, thanks guys. So it's a case of go for a 10spd cassette 11/36 and maybe try that first,

    But bear in mind that if you change the cassette to 10 speed you have to change the derailleur and shifter as well, anyway.
  • Alan P
    Alan P Posts: 127
    Good point....I forgot about the shifter! Thanks
    Ibis Mojo HDR (2014)
    Canyon Grand Canyon AL29 (2013)
  • The Rookie
    The Rookie Posts: 27,812
    And chain of course......
    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.
  • Alan P
    Alan P Posts: 127
    This is getting more expensive for him by the minute!
    Ibis Mojo HDR (2014)
    Canyon Grand Canyon AL29 (2013)
  • njee20
    njee20 Posts: 9,613
    It's been said - but you know he needs a rear mech as well, worth repeating!
  • FishFish
    FishFish Posts: 2,152
    ..and a steeper hill of course. And a new car to get him there.
    ...take your pickelf on your holibobs.... :D

    jeez :roll:
  • Alan P
    Alan P Posts: 127
    And the list goes on....
    Ibis Mojo HDR (2014)
    Canyon Grand Canyon AL29 (2013)
  • and a small bank loan :D
  • The Rookie
    The Rookie Posts: 27,812
    To summarise...
    9-10 speed means cassette, chain, shifter and mech UNLESS you use Shimano flat bar road shifters when you can use a 9 speed mech.
    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.
  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    Man up and do without the range expander. With a 32t up front it shouldn't be too tough.