Leaving work Monday, I get downstairs and my tire's flat. I patch the tube and ride home.
Next morning, it's flat again. A different puncture. I replace the tube and leave for the office.
I get a new flat on the ride to work. Patch the tube and keep going.
I get downstairs that evening, and the tire has gone flat again. I take the train home.
What's going on? I'm pretty confident in my tube patching abilities, and every time it's been a new puncture, in a different spot in the tube. I scoured the tire for glass, rocks, anything embedded that could be causing punctures. Nada. The tubes have been fully inflated and seated properly.
Two possibilities stand out in my mind. One is that it's a 32 mm tire and the replacement tube was 25mm. But that doesn't explain the two flats on the old tube, which was a 32 mm tube. Maybe the first two flats were bad luck, and the second two were from using too small a tube? My understanding is that you can usually get away with using small tubes, but maybe I'm wrong.
The second thing I noticed is that the tire is getting pretty worn out. It's not at risk of blowing out any time soon, but there's some cracking in the sidewalls and a couple irregularities on the inside of the tire. Could having a worn tire cause so many flats so frequently?
What do you think, bikeforums? Coincidence? Bad selection of tubes? Time to replace the tire? Is there anything I'm not thinking of?