smallest cassette to use

sl2371
sl2371 Posts: 748
edited August 2012 in MTB workshop & tech
hi all i have just got a 29er mountain bike and i want to use it for road work to so i bought another set of wheels
my question is
i have a 36-12 rear cassette on at the moment what would be the smallest size cassette i could put on my spare wheels
and would it affect my rear mech with say a 28-12 cassette would i have to adjust my rear mech every time i switched wheels
cheers

Comments

  • nicklouse
    nicklouse Posts: 50,675
    what do you mean by smallest?

    do you want a higher gear? or closer gears?


    fit any you want with a 11T small cog of the same speed.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • sl2371
    sl2371 Posts: 748
    i want a closer gear ratio for road use i just wondered if a long cage rear mech would be ok with a closer ratio cassette
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Makes no difference, will just move less.
  • sl2371
    sl2371 Posts: 748
    ok thanks
  • nicklouse
    nicklouse Posts: 50,675
    sl2371 wrote:
    i want a closer gear ratio for road use i just wondered if a long cage rear mech would be ok with a closer ratio cassette
    it will work fine just re set the B screw.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • sl2371
    sl2371 Posts: 748
    i was hoping to not have to adjust any thing so i will probably go with a larger ratio cassette :?
  • njee20
    njee20 Posts: 9,613
    You won't need to adjust the b-screw, the top jockey will just sit further from the cassette. More of an issue going the other way.

    It's not a big issue either way.
  • cooldad
    cooldad Posts: 32,599
    Going from 36 to 28 you'd probably need to shorten the chain.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • bails87
    bails87 Posts: 12,998
    cooldad wrote:
    Going from 36 to 28 you'd probably need to shorten the chain.
    Why?

    The 'smallest' (in terms of teeth on chainring + teeth on cassette) gear would be the same as on a MTB cassette, if they both end with a 12t cog.

    He could shorten it a bit but wouldn't need to.
    MTB/CX

    "As I said last time, it won't happen again."
  • cooldad
    cooldad Posts: 32,599
    bails87 wrote:
    cooldad wrote:
    Going from 36 to 28 you'd probably need to shorten the chain.
    Why?

    The 'smallest' (in terms of teeth on chainring + teeth on cassette) gear would be the same as on a MTB cassette, if they both end with a 12t cog.

    He could shorten it a bit but wouldn't need to.
    Because you measure big/big and the big at the back is now 8 teeth smaller. I would anyway, just makes sense to my brain, although I do see your point, kind of.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • sl2371
    sl2371 Posts: 748
    hi guys thanks for all your comments the smaller cassette on my spare wheels would not be used all the time
    so shortening or adjusting the b screw is not something i want to do all the time
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    That will be the least of your worries unless you use a chain to match each of your cassettes.
  • njee20
    njee20 Posts: 9,613
    If you stay on top of chain wear, swapping wheels (and cassettes) isn't a problem. Change chains when they wear and you'll be fine.

    No reason to shorten the chain, if you were changing both cassettes to a 12-28 I would, but no point doing it for spare wheels.
  • sl2371
    sl2371 Posts: 748
    so a 28t sprocket will be ok
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Yes.

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