Originally Posted by
bikepro
As noted in prior posts, there are numerous options for cassettes with a low cog of 27 or more. However, you need to check the capacity of you current RD. If you go from 25 to 27,or more, you may need a different RD. Since you have SRAM, I recomment their WiFLi (
https://www.sram.com/sram/road/technologies/wifli) RD. This will give you more than enough capacity. You will also need to replace the chain since the larger cog will require a longer chain.
I don't think that SRAM has made a road RD that won't handle a 27t cog.
As an aside, you and I have probably the only two Look 585s (mine's an Optimum) in a 500 mile radius.
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Regards,
Chuck
Demain, on roule!