GTPilot wrote:queequeg wrote:
A little tip that Duck! gave me on chain length. Size it based on the small/small combination instead of large/large. That way, your chain is the correct length for the capacity of your rear derailleur, regardless of what cassette you throw on it. This is very handy if you have multiple wheelsets with different cassettes, or you are like me and have a climbing cassette and a racing cassette that I swap between.
If you have the chain running through your derailer when sizing it yes, could not agree more, so long as you only apply enough tension for the chain not to rub on the cage as it passes back under, this - especially when running a short (SS) cage and larger cogs and chain rings. Otherwise no.
I've always used the method of no derailer big ring to big cog - plus one inch(one full link set) Always seems to work for me.
That's exactly how it works. If I know it's getting marginal on system capacity I'll mark the pin I intend to cut at, and check on the big/big combo, leaving the chain through the derailleur just to be sure. This step is more important on rear-suspension MTBs where the movement of the rear linkage increases the effective chainstay length, so that needs taking into account.