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Will cassette fit

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  • 17-05-2014 9:53am
    #1
    Salmonman
    Registered Users Posts: 99 ✭✭


    I have a carrera tdf and it has a 12/26 on the back which is a bit of hard work up hills.Looking at upgrading to an 12/28 ultagra which is 11 gears(I think) where as the tdf only has 8 gears. Will it fit
    Thanks


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    #2
    TonyStark
    Registered Users Posts: 851 ✭✭✭TonyStark


    Salmonman wrote: »
    I have a carrera tdf and it has a 12/26 on the back which is a bit of hard work up hills.Looking at upgrading to an 12/28 ultagra which is 11 gears(I think) where as the tdf only has 8 gears. Will it fit
    Thanks

    I think you probably would need a new chain. From my limited experience the widths of the chains are different. As the space between the cogs is different. Open to correction.


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    #3
    bren_mc
    Registered Users Posts: 430 ✭✭bren_mc


    I'm afraid it wont be compatible. If your shifters are 8 speed, then your cassette will also have to be an eight speed. However, you may well be able to find an eight speed cassette with a bigger sprocket.

    Edit: Just had a look on wiggle - Sram do an 11-28 but is out of stock at the moment and also a 11-32 (though I'd imagine that would feel like huge gaps between the gears and probably also need a longer rear mech)


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    #4
    Borderfox
    Moderators, Sports Moderators Posts: 10,257 Mod ✭✭✭✭Borderfox


    Might be easier to change the front ring


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    #5
    DubVelo
    Registered Users Posts: 581 ✭✭✭DubVelo


    As said above you need an 8 speed cassette, the shifters won't work etc.

    I swapped the front for a compact crankset on mine.


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    #6
    ezra_pound
    Registered Users Posts: 2,497 ✭✭✭ezra_pound


    I just fitted a 12/30t cassette without changing anything else. It seems fine but haven't ridden it yet. Just need to slightly adjust front mech for engaging 38:30 gear. Just a millimetre should do it.

    The rd 2300 derailleur claims to only handle maximum of 11/26t. Am I going to ruin my derailleur if I cross gear? Or if it looks fine will I be grand?

    Sorry. Just to clarify this is on the Carrera tdf.


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    #7
    ezra_pound
    Registered Users Posts: 2,497 ✭✭✭ezra_pound


    Follow on from last post:

    I adjusted low limit for front derailleur and all the gears seem to work smoothly. I gave it a quick cycle and was just cautious not to cross chain. Will check chain length shortly and see if I should add a bit. But other than that it seems OK.

    Am I fooling myself though? If spec for derailleur is Max 26t, is something going to give?


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    #8
    TonyStark
    Registered Users Posts: 851 ✭✭✭TonyStark


    ezra_pound wrote: »
    Follow on from last post:

    I adjusted low limit for front derailleur and all the gears seem to work smoothly. I gave it a quick cycle and was just cautious not to cross chain. Will check chain length shortly and see if I should add a bit. But other than that it seems OK.

    Am I fooling myself though? If spec for derailleur is Max 26t, is something going to give?

    How many speed is the rear cassette?


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    #9
    quozl
    Registered Users Posts: 3,308 ✭✭✭quozl


    Gently put it into big front ring and biggest sprocket while stationary at home and see if it can do that or if that would damage the derailleur. I know you can keep out of that combination but I'd be worried about accidentally doing it some time while the chain is under load and ripping my derailleur to shreds.

    That said,

    If it's specced for a max of 26teeth then that's going to have to work with a compact double which has a teeth difference of 16 in the front.
    IIRC those carrera TDFs have a standard double (53-39) on the front, a 14 tooth difference. So by having that you've already bumped the rear dereillaur to equivalent of supporting 28 teeth.

    Then shimano build in a margin for error in their derailleur specs. I've seen 2 teeth mentioned numerous places as fairly safe. I'm using 2 teeth over on my own rear derailleur with no problems. So I'd say a 30, with a standard double is a pretty safe bet.

    Again, that's assuming the chain is long enough. If the chain is too short then it doesn't matter what the rear derailleur's capacity is - you have the potential to break it if you shift into the wrong gear.


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    #10
    ezra_pound
    Registered Users Posts: 2,497 ✭✭✭ezra_pound


    quozl wrote: »
    Gently put it into big front ring and biggest sprocket while stationary at home and see if it can do that or if that would damage the derailleur. I know you can keep out of that combination but I'd be worried about accidentally doing it some time while the chain is under load and ripping my derailleur to shreds.

    That said,

    If it's specced for a max of 26teeth then that's going to have to work with a compact double which has a teeth difference of 16 in the front.
    IIRC those carrera TDFs have a standard double (53-39) on the front, a 14 tooth difference. So by having that you've already bumped the rear dereillaur to equivalent of supporting 28 teeth.

    Then shimano build in a margin for error in their derailleur specs. I've seen 2 teeth mentioned numerous places as fairly safe. I'm using 2 teeth over on my own rear derailleur with no problems. So I'd say a 30, with a standard double is a pretty safe bet.

    Again, that's assuming the chain is long enough. If the chain is too short then it doesn't matter what the rear derailleur's capacity is - you have the potential to break it if you shift into the wrong gear.

    Thanks.

    That sounds like sense re compact / standard allowing me to get away with it.
    So far it all seems fine but I'm being careful!


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