Changing Cassette

Discussion in 'Australia and New Zealand' started by Ian, Mar 14, 2005.

  1. Ian

    Ian Guest

    I have been following the thread about the gears, however it went all over
    the place.

    Anyway my question is, if I change my cassette from a 12 - 25 to a 12 - 27,
    will it cause any problems with smooth changing.
    Is it just a simple changeover that won't cause any other problems ?

    Ian
     
    Tags:


  2. ritcho

    ritcho New Member

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    It should change fine. The only concern is whether your chain is long enough. A 27T rear cog takes up more chain. If the chain is not long enough, it will destroy your rear derailer. Check to ensure there is just enough chain in the big-big combination and you'll be fine. Not that you'll ever want to use the big-big combo, but it's nice to have enough chain to prevent yourself from accidentally wrecking your derailer.

    Cheers,
    Ritch
     
  3. adam

    adam Guest

    "Ian" <[email protected]> wrote in message
    news:[email protected]
    >I have been following the thread about the gears, however it went all over
    > the place.
    >
    > Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -
    > 27,
    > will it cause any problems with smooth changing.


    Nope, just check the chain is long enough but you should be ok. Check out:
    http://www.sheldonbrown.com/derailer-adjustment.html#chain

    > Is it just a simple changeover that won't cause any other problems ?


    Yep

    Adam
     
  4. Geoff

    Geoff Guest

    "Ian" <[email protected]> wrote in message
    news:[email protected]
    >I have been following the thread about the gears, however it went all over
    > the place.
    >
    > Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -
    > 27,
    > will it cause any problems with smooth changing.
    > Is it just a simple changeover that won't cause any other problems ?
    >
    > Ian
    >
    >


    Shouldn't be a problem. Assuming you are running a double on the front and
    a standard short cage derailleur. You may need a small adjustment to the
    rear mech to stop it from hitting the bigger 27T sprocket and depending on
    your current chain length you might need to add a couple of links.
    Personally I've only had experience changing between cassettes with a 19T,
    23T or 25T top end but I know a couple of people that run a 27T with a short
    cage. Anything bigger than a 27T may need a different derailleur with a
    longer cage.

    Flyingdutch may be able to give you a better qualified answer when it comes
    to the jump from 25T to 27T but I think he's currently running a long cage
    derailleur.

    Geoff
     
  5. stu

    stu Guest

    "Ian" <[email protected]> wrote in message
    news:[email protected]
    > I have been following the thread about the gears, however it went all over
    > the place.
    >
    > Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -

    27,
    > will it cause any problems with smooth changing.
    > Is it just a simple changeover that won't cause any other problems ?
    >
    > Ian

    its a simple enough changeover if you have the tools.
    its is a cassette right??? http://www.sheldonbrown.com/free-k7.html
    the 2 biggest worries i can think of are, how old is the chain? it might be
    to worn to fit a new cassette.
    if it isn't worn, is the chain long enough to go big-big?
    http://www.sheldonbrown.com/derailer-adjustment.html#chain
    hope this helps

    stu
     
  6. Random Data

    Random Data Guest

    "Geoff" <[email protected]> wrote in message news:<[email protected]>...

    > Anything bigger than a 27T may need a different derailleur with a
    > longer cage.


    I've run either a 12-32 or an 11-30 cluster with an XT short cage, and
    been able to use 22/32/42 chainrings with it. You can't go big-big and
    still have usable tension in the lower gears, but unless you're really
    mashing the shifter you can feel that the derailleur doesn't want to
    go into a gear, and stop before you break it.

    However, the XT short cage may have been the equivalent of a road
    "medium cage". It's been so long since that derailleur went to the
    parts bin I can't remember just how long the cage was.

    Dave - who had about a year span of breaking a derailleur between
    every 4 and 6 weeks. That was expensive.
     
  7. Marty

    Marty Guest

    Random Data wrote:
    > "Geoff" <[email protected]> wrote in message news:<[email protected]>...
    >
    >
    >>Anything bigger than a 27T may need a different derailleur with a
    >>longer cage.

    >
    >
    > I've run either a 12-32 or an 11-30 cluster with an XT short cage, and
    > been able to use 22/32/42 chainrings with it. You can't go big-big and
    > still have usable tension in the lower gears, but unless you're really
    > mashing the shifter you can feel that the derailleur doesn't want to
    > go into a gear, and stop before you break it.
    >
    > However, the XT short cage may have been the equivalent of a road
    > "medium cage". It's been so long since that derailleur went to the
    > parts bin I can't remember just how long the cage was.
    >
    > Dave - who had about a year span of breaking a derailleur between
    > every 4 and 6 weeks. That was expensive.


    The instructions that come with Shimano derailluers tell you what sort
    of gear sizes you can run. There's a little formula you have to work it
    out.

    I also had a bad run on derailluers and have a box with three brand new
    ones on standby. Yes it is expensive. Since getting the spares a few
    months ago I haven't had any failures, Touch Wood! (Touches head).

    Marty
     
  8. Ian

    Ian Guest

    Thanks guys , much appreciatted.
    "stu" <[email protected]> wrote in message
    news:[email protected]
    >
    > "Ian" <[email protected]> wrote in message
    > news:[email protected]
    > > I have been following the thread about the gears, however it went all

    over
    > > the place.
    > >
    > > Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -

    > 27,
    > > will it cause any problems with smooth changing.
    > > Is it just a simple changeover that won't cause any other problems ?
    > >
    > > Ian

    > its a simple enough changeover if you have the tools.
    > its is a cassette right??? http://www.sheldonbrown.com/free-k7.html
    > the 2 biggest worries i can think of are, how old is the chain? it might

    be
    > to worn to fit a new cassette.
    > if it isn't worn, is the chain long enough to go big-big?
    > http://www.sheldonbrown.com/derailer-adjustment.html#chain
    > hope this helps
    >
    > stu
    >
    >
     
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