I'm planning to redo my crankset and gearing this winter. I currently have a set of 175mm E13's, but will probably switch to 170's. I'm looking for a bit more ground clearance, and a little bit more leg comfort (I prefer a shorter crank length.) My question is, should I factor this length reduction into my gearing? The Sheldon Brown gearing calculator shows that those 5mm's can mean a difference of 1 tooth up front. In looking for greater ground clearance, I may go with a smaller cog, and a spiderless crank so that I can run a smaller front ring. Looking at running 28/9 x 16 which is similar to my current setup. Just curious as to others opinions.