[Beav]

As the vibration becomes more and more pronounced, the closer you are to having a blowout. Tires never "...just blew out!" from defects, they always issue a warning beforehand. If no warning is issued beforehand a blowout is caused by a road hazard.

The edge wear you have could be caused by a tire defect, a result of a road impact or from a bad alignment, whether due to worn parts, bad adjustment or normal wear and tear.

It seems that you really need to have a pro look your car over. It's a good thing to be able to do your own maintenance, but sometimes it's also good to have a knowledgeable, trained person to double check things. Sometimes it can end up being less expensive in the long run, versus 'fixing' things that weren't bad to begin with.