I was taking a bicycle maintenance class, and the first thing we did was learn how to swap tubes. I decided to get new tires for my 81 SR at the same time and had the teacher help me pick them. They are wider than my old one. I have the numbers, if it's important.

Anyway, the fit of the new tires was a lot tighter. He helped me get the last hard bit in. I saved the other tire to put on at home, but never got to it. Didn't ride or touch the bike. Next week when I went in, the bead had popped out in one spot.

He was surprised, and said, "that's the one we did together, right?"

So now I'm a little freaked about it. Should I just chalk it up as an anomoly, or is it a sign of something being awry?