I'm trying to understand these numbers too (I looked at the women's version of that bike yesterday).
Is there a web site that explains "gears for dummies"? Whenever someone says "I replaced it with x/y/z", I wonder how to translate that, and how they knew what to ask for. I've looked around for info but not sure how to search for it.
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Specialized Roubaix Expert
Surly Long Haul Trucker