kengr

Well, the bike had sat for several years with the tires essentially flat, then I pumped them up to close to max pressure.

And it may have warmed up some too.

Anyway, I'm gonna take it to the bike shop and have them replace the tube and check the tire and rim for problems.

On a previous bike I had to replace a tire once because the bead that hooks onto the rims was gone in one spot and that let the tube bulge there. Kinda hard to patch a six inch linear break in the tube... :-(