Bald street tires are actually pretty good at auto-x, however the difference from bald to corded is a pretty fine line on these tires and you are at greater risk of a severe puncture.
They are no where as sticky as a race slick though and most of the gain you get is from absence of tread squirm and a slightly larger contact patch. I always went slower at auto-x when I replaced my tires, was very disappointing
