[Jesse Knapp]

At the speed Pro Stocks go, what is the air doing at the front tires? Could it move more smoothly around a tire without grooves? I would think this is a possible reason. I also think a bald tire allows more contact and more friction to slow you down, but one could pump more air in that bald tire getting it up off that surface a bit so there is no loss from that. I believe aerodynamics is why they are doing this. Just my opinion.