Most would agree that bald tires have less traction, but why? Aren't racing slicks the perfect example of a tire that is bald yet has good traction? I realize racing slicks usually use different compounds but there is a reason why there are no tread grooves in the tires, it's so that there is more rubber contact with the road. I'd understand that in wet conditions you're absolutely screwed with racing slicks and or bald tires, but in dry conditions, shouldn't bald tires that aren't meant to be "bald" provide better traction and worse fuel economy than new tires that have grooves?

 

1) Compound is not necessarily static through the entire tread depth. Meaning, you might not be on the same type of rubber once the tire is bald.
2) Bald tires have been in use for some time, and tires get harder and grip less as they age and harden.
3) Sand, dirt, or water on the pavement = with bald tires.
4) Heat. A bald tire can't dissipate heat as well as one with tread. (someone verify this please)

That said, I run my RT-615 Azenis past bald. If they ain't corded yet, they still get autocrossed. But I would never drive them on the street with less than 1/32" of tread, and even that is seriously pushing it. My daily driver tires get tossed at 2/32". My safety (and my passengers' safety) is not worth risking it.