Bulging Tire / Sidewall
I picked up an 80s steel road bike a few months ago. After riding on a pair of 700 x 25c tires, I decided to try a pair of 700 x 23c's (Continental Ultra Race).
The rear tire went first, in about 100 miles. Not 100% sure what happened, but I think I got a pinch flat. When it popped, it went off like a shot, blew out the sidewall and obviously destroyed the tire.
About 100 - 150 miles later, the front tire is having issues. I was riding along, no particularly bad bumps, and the tire bulged outside of the rim on both sides. I stopped immediately, deflated the tube, re-seated the tire, re-inflated it, no problems, didn't really think about it.
Today, riding on some moderately rough roads but nothing too bad -- I didn't hit anything worse than train tracks. Got another flat; swapped the tube; and when I re-inflated, the tire bulged over the rim right at the valve. Deflated the tube, moved the tire, reinflated, bulge at the same spot. Did it a 3rd time inflating very slowly and it was ok. (The previous major bulge was NOT at the valve iirc).
BTW, no problems like this until I put the Continental tires on -- just one puncture flat in about 1000 miles.
So does this sound like shoddy tire construction, or an issue with the wheel(s)? Is there a way to figure this out other than taking it into my LBS and having them check it out?