shimano rear mech / cassette compatibility

evsy
evsy Posts: 111
edited October 2013 in Workshop
Hey

I have a compact chainset on my bike (34/50) and a 12/30 cassette.
I don’t think I have ever needed to use the 30 and sometimes find myself getting dropped on long descents despite spinning as fast as I can. So I have been thinking about changing the chainset for a double, but a few of the lads have said its cheaper just to buy an 11/25 or 11/23 cassette.

Anyway, what I was wondering is if I do that will my rear mech need changing as well (i think its a medium - gs - mech)? Or will it be ok to run a 11/25 or 11/23 cassette on it?

Thanks

Evsy

Comments

  • arlowood
    arlowood Posts: 2,561
    Your rear mech will be fine - no need to change that. Your chain might end up being too long so you might need to take out a couple of links (or more)

    Use this link to check the difference between the optimum lengths for different cassettes based on largest rear sprocket and 50 tooth front ring. You'll need to measure your chainstay length also.

    http://www.epicidiot.com/sports/chain_l ... tm#results
  • evsy
    evsy Posts: 111
    arlowood wrote:
    Your rear mech will be fine - no need to change that. Your chain might end up being too long so you might need to take out a couple of links (or more)

    Use this link to check the difference between the optimum lengths for different cassettes based on largest rear sprocket and 50 tooth front ring. You'll need to measure your chainstay length also.

    http://www.epicidiot.com/sports/chain_l ... tm#results

    thanks for your response. just the info i needed!

    thanks

    evsy

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