Originally Posted by
pdlamb
I remember reading an essay (in Buycycling?) 15-20 years ago that waxed poetic about a 16 tooth cog. I haven't come up with a reason to move that out of the "senseless fixation" mental file. (Put on a 17 tooth instead, crank it up to the same cadence, and you'll go 6% faster!)
Actually, you’ll be slower at the same cadence running a 17 tooth cog, since this number goes in the denominator of the gear inch calculation.
Switching to a 15 is what you are thinking of as a faster gear.
For example, I used to ride 42/17 SS and it was too slow (66.7 gear inches) for cruising, so these days I’m running 42/16 (70.9 gear inches).
I have nothing against odd numbers, but I suspect 42/15 (75.6 gear inches) would be a bit too much up the hills, at least at present.
Otto