A cautionary tale --

While walking home from the train station yesterday, I met a gentleman who had just replaced a blown-out front innertube. He had a modern bike with (presumably) hook beaded rims, so I don't know what went wrong in his case.

However ...

This morning I suffered the same fate during the last 4 miles of a 25-mile ride. I was using an old Weinmann smooth-sided 27" rim and a Vittoria Zaffiro tire, inflated to 80 lbs when cold at 6:45 a.m. By 8:30, the ambient temperature had increased by 15 degrees F, and this, coupled with the heat generated by rolling and braking, probably pushed the pressure above a safe level.

I was going slowly at the time and brought the bike to safe stop, but this has scared me into giving up on smooth-sided rims and backing off to 70PSI until bead hook-sided replacements arrive.