Building up my first SS which has a 42 tooth chainring. Trying to decide between a 17 or 18 cog. I live in Southern NH, always mildly hilly. I'm 135# and a good climber. Like to spin relatively high cadences.
Used a gear inch calculator; for my setup, 42-17 is 68.2 inches and 42-18 is 64.4 inches.
On my road bike, I tend to favor 53-19 (77) or 20 (73.1) on the flats, 39-21 (49.6) or 23 (45.3) on moderate hills.
So . . . which might be the better choice for me? Or am I thinking of this all wrong? What else should I be considering in making my choice?