so i'm building a fixie, but i think i just ran into a slight problem. the only chainring that i can use from this bike is a 52 tooth.
i know that most people here run 42 tooth, or sometimes something like 46 for taller gearing.
i want to start off with the equivalent of a 42x17 (don't know what that is in inches), which by my calculations, would be 52x21, so i need a 21-tooth cog.
what are you recommendations for this situation? should i shell out for another crankset or find a used crankset with a usable 42T ring, or is the 52x21 ok?