might be covered by warranty if no sign of hard driving on tire.

 

No matter what a new tire won't cost you $800 that's for sure, don't worry about bypassing the "tire coverage" - they're usually pretty crappy anyway (ever read the fine print, geez).

 

They can usually determine if a sidewall bubble is caused by an impact by looking at the inner sidewall. If the bulge is from an impact, there is usually a cut or line of some sort on the other side of the bubble. If it's a manufacturing defect, then there is no cut.

Chances are, the bulge is a result of an impact...