Hey,
I am new to the fixed gear scene. I usually ride my Cannondale R400S (and even with that I am not too Bike savy). But I decided to build a fixed gear and really break into biking as not only a hobby but a way of life. Anyway, I already bought a 50 tooth chainring and crankset but I am not sure of what to do with my rear cog. My uncle told me to go with something in the 'teens. I will be doing minimal uphill / downhill, mostly city and flatland riding. Please advise. Thanks.