I got my second flat front tire in about a month today. Both times I could not find anything in the tire that would have caused it.

The hole is on the side of the tube. I still have the tube I patched from the first flat, and the holes aren't in the exact same place, but they are close (couple of inches apart).

Is this just coincidence, or could I be missing something? The tire looks fine. I checked the wheel, too, and didn't find a rough place. The tape is okay.

Also, did I do any damage by rolling the bike-with-flat-tire about a mile to the subway? Both tire and wheel look okay.