I'm not trying to start a fight or anything, but there's something I've never understood about this argument. I get the clearance thing, because I'm sure any little bit helps, though, for the record I have 170's on my fuji track and I've NEVER struck even after cornering pretty damned fast. I think I read somewhere that the fuji track has a nice higher bottom bracket.

But the idea that it's going to produce any noticeable difference in torque is absurd, if I remember my physics correctly. Torque is directly proportional to the distance (from the center of rotation) from which it's applied, which in this case is the crank arm. So you're talking about a 2.94% decrease from 170's to 165's.

Correct me if I'm wrong, but maybe this is just another case of people trying to sell you **** you don't need?