Originally Posted by lbthomps
from that chart it looks like 17t cog would be the best with respect to number of skid patches especially if you want to chang the chainring and not lose the number of skid patches available...maybe I'm just saying this because thats what size cog I run
well, really what you want are cog/chainring combos that are prime, relative to each other.
34t and 51t are outside the range of what most people ride on the street, so 17 works well.