Originally Posted by
cyclezen
Only you're gonna know what works for you...
so you say a 39/26 is not small enough (from your cassette 12-26 ?) which is 42 inches.
pick the gear you think will work to do the climbing - say a 34 inch gear, and put it into a gear calculator - along with all the other gears...
here's a visual calculator I like:
Mike Sherman's Bicycle Gear Calculator
& one which allows you to easily drag the gears around to get different combos:
HTML5 Gear Calculator
look at the ranges around which you'll have to double shift and see of this is OK - having to double shift in gear zones which you use constantly is a GIANT PITA.
Those are very helpful calculators, thanks! It makes me understand better the differences between all the combos.
I think I might end up going with a 50.34 in the front, but also switching out to a 11-28 in the rear. Seems like this would give me a better spread of gears while staying on the small ring in the front.
It seems like the 34-28 would give me plenty of climbing capacity, while the 34-11 would still allow me to go pretty fast without shifting in the front (as opposed to 34-12).