Originally Posted by
ZippyThePinhead
What did you use to make the chart above?
The first bike I had that I rode seriously had a triple and I just figured I needed it. My lowest gear was 28/32 (22") and I used it for one climb in particular. Then I started riding a road bike where the lowest gear was 42/28 (41") and when I was able to do that particular climb, I realized that maybe I could live without the triple. Now I ride a compact double where the lowest gear is 34/28 (32"), and I no longer care to have a triple. Mabye when I am older...
I wouldn't choose to ride a double if I wasn't strong enough to handle a big cog that let me have one tooth jumps up to the 19.
With 10 cogs and 11 starting that allows for a 21 large cog, 23 with a 12 first position, and 26 with a 13 starting cog.
With only 9 in back the numbers are 19, 21, and 23 respectively.
Even then the double isn't necessarily better - although 50-34x13-14-15-16-17-18-19-21-23 has the same range and gear spacing as 50-40-30x13-14-15-16-17-18-19-21 disregarding the fully cross-chained combinations only 50x21 and 34x14 overlap so there's a lot more double shifting with the wrong terrain/wind/fatigue or rest day combinations and both gears near the ends of the cassette are noisier than the equivalent 40x17 in the middle.