any truth to this idea about flat tires??

[jetuomi]

I've had two sets of z-rated tires, no flats or blowouts.
but for 3 months I had a set of 180km/h rated (can't remember the letter) and the rear blew out on me..

with my moms car, she gets flats once a year.

Is this because the z-rated have thicker sidewalls, stronger steel belts, and generally can handle more abuse??

I've always wondered about this, why you never see vettes and stangs, etc on the side of the road, but mainly corolla's and tempo's....