changing cassette

jamsop
jamsop Posts: 51
edited January 2010 in Road beginners
Hello,

Currently I have a compact crankset with a 12-25 cassette. I am thinking about getting a 12-27 cassette for routes that are more hilly.

I may have to adjust the B-screw on the rear mech but will i need a new longer chain when changing over to a 12-27 cassette?

Thanks

Comments

  • andy162
    andy162 Posts: 634
    I think your chain will be ok. I swap between a 25 & 27 cassette with no problems.
  • salsarider79
    salsarider79 Posts: 828
    There is only one way to find out. If your chain is tight on the Big to Big rings then it'll be too short. You should not be riding in big to big nor small to small as it's really bad for the chain. :wink:
    It's also not necessary to adjust the b screw unless the rear mech hits the cassette, which is unlikely given you already run a 25t.
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  • rickhotrod
    rickhotrod Posts: 181
    It would be useful if Shimano made a 13/28 cassette. I don't like the 12/27 (12,13,14,15,16,17,19,21,24,27) because when on the big ring the jump from 21 to 24 is too big. 12/26 (12,13,14,15,16,17,19,21,23,26) would be better. SRAM might make that size.
  • SCR Pedro
    SCR Pedro Posts: 912
    rickhotrod wrote:
    I don't like the 12/27 (12,13,14,15,16,17,19,21,24,27)

    I totally agree. The jump from 24-27 is too much. I can do most stuff on a 12-25, but having a 27T would be useful for some of the steeper stuff. I used to have a 39/28, and got up anything I attempted. I reckon 25 would be pushing it on some insane gradients though.

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  • John.T
    John.T Posts: 3,698
    rickhotrod wrote:
    It would be useful if Shimano made a 13/28 cassette. I don't like the 12/27 (12,13,14,15,16,17,19,21,24,27) because when on the big ring the jump from 21 to 24 is too big. 12/26 (12,13,14,15,16,17,19,21,23,26) would be better. SRAM might make that size.
    Just use the 34 with 14,15 and 16. It covers the same range. I seldom use beyond the 21 on the big ring.
    I think the 12/25 is too close on the big sprockets when using the 34 ring. 12/27 is better.
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