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Old 06-24-09, 06:21 AM
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djohannsen
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Originally Posted by Garthr View Post
I like the idea of using the 11-21 or 11-23 for you Dave. You never want to use the 30/smallest cog or 52/largest cog anyways, it really stretches the chain. Use this gear chart and you can see how it works for you. Put in any rings you want . http://home.earthlink.net/~mike.sherman/shift.html
I'm on an 11-23 now. I didn't know (until now) that Shimano made an 11-21. Since I've got the option of the really small ring with a triple (i.e., the 30), this might be a nice route to go. As for the crossed gearings, It's really the two or three crossed gears that cause the chain to rub on the front derailleur (not just the smallest and largest cogs). I thought that with a double that this problem would be mitigated allowing me a wider range of shifts without having to jump between chain rings. To be honest, I'm sure that part of my desire to get off the triple is the fact that I've got my first race coming up in a couple of weeks. There's certainly a bit vanity and insecurity on my part in not wanting to be the only dude in the field on a triple.

Thank you also for the pointer to the calculator; it allowed me to see for myself that you're absolutely right that the change from a 52 to a 54 doesn't amount to much of a difference at the top end. I was hoping that adding a couple of more teeth on the big chainring would make more of a difference.

Finally, thank you for all the time that you've generously taken to help me. It sounds like maybe I should scrap the plan of changing to a double. Instead, I can move to an 11-21 the next time I do a chain and cassette replacment (I've got a lot of miles on my current ones, so this will be pretty soon). I can then start squirrelling away money for the probably not too distant grouppo purchase (since my 105 components are now approaching seven years of service).


Dave
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