Update: this question is NOT about how to calculate the # of skid patches. I've always used http://www.bikecalc.com/skid_patch_calculator for that and the math is sound.
So, I'm already thinking ahead to next winter to see what I could do better with my fixed gear winter commuter. I'm running a pretty conservative gearing with a deliberately odd-numbered cog (21T I believe) to spread the skid patches all over my rear tire (update: I'm running 44x21 so 21 skid patches, which is a lot). This winter I tried the Schwalbe Marathons and was pleased generally, but after only two months of daily riding, the rear tire looks like the tonsure on a monk's head: completely bald in the middle and treads on both sides.
Why? Because I have SO MANY skid patches that it's a pretty uniform wear. And I hear that the Schwalbes use a pretty soft compound so they wear fast.
So, I'm wondering, what if I switched to an even gearing with **LESS* skid patches? Like a 45x20 for 8 skid patches. Obviously, some parts of the tire would wear more... but others would keep their tread... Has anyone tried this and is it a horrible idea? Or is there some merit? Again, I'm focusing on WINTER riding where I might want to preserve a little tread for grip.
And yes I run a front brake.