That's funny -- I had a flat on my second ride on my new road bike. I've changed flats on my hybrid -- and I carefully paid attention. This time, however, it was getting dark, the brakes were different (it took me a few minutes to figure out how to disconnect them), the road tire was a lot harder to get off than any other flat I've changed, and in all the haste I didn't pay attention to which way the tire went. I've been wondering if it matters (but not wondering enough to look closely at the tire). It doesn't seem to have much tread, so I presumed no.