Andy_K 

I know there are a few other people here who use their cross bikes for both commuting and cross racing.

Question: how do you keep from wearing down the tread on your cross tires? Or do you just not worry about it?

I use road tires on my bike most of the year, but when cross season comes around, I swap on the knobbies. I've got two sets of wheels, but it turns out the rims are different widths, so it's not a quick change. Plus there are some mid-week cross activities I have been and will be going to straight from work.