[blipshift]

Is it A) street tire tread roll-over with potential for chunking. B) Upper side-wall rubbing in a turn. C) All of the above. D) None of the above.

My understanding has always been A) based on this general line of thought...

http://www.gttrackdays.com/tires.html

...but have gotten into a healthy discussion on upper-side wall roll over which also makes sense.