Sounds like some impact caused some of the threads in the casing to be damaged, where when riding, they broke, causing the bulge, which caused the tube to blow. Not all that uncommon.
Thanks for the response. I'll need to take this apart and see if the problems was the stitching or the casing. If it is the casing, is it repairable without a herculean effort?
Sounds like in the future, I need to stop riding asap and change the tire. Avoids having to repair the tube inside, possibly.
