Tired tubes

After 20 years of riding and repairing bicycles, I'd never seen a tube fail with a pattern like the one in the top photo. It turns out, this is how a tube will fail if you have a poor-quality nylon rim strip that is tearing imperceptibly.

The second photo shows the inner wall of a tire in pre-failure mode. I noticed that the sidewall felt a bit irregular when the tire was at full pressure. So I unmounted it, and lo! Not sure how it got that way, but I suspect the tire may have been manhandled a bit sometime in the past either during mounting or unmounting. It is good to inspect your equipment regularly!