Zipp knew that they had eventually had to address tires. Because they cover the wheels and spin faster than any other part of the wheel, the aerodynamics of the tire are important. That's why Zipp took the time to develop their own tire, the Tangente Clincher Tire.
The tire took not only lots of time to design, but trips to the wind tunnel to perfect. As a result, the Tangente is a pretty unique tire. Rather than giving a round profile, this tire has a point at the top of the tire, extra rubber to change the overall shape that the tire presents to the wind. On the shoulders, you'll find ABLC dimples that work in two ways. First they smooth out airflow. Second, they help adhere the tire to the ground better than a file tread.
The casing is a 290 TPI tire casing from Vittoria with a thread count on par with other top-shelf racing tires. The bead is foldable, not so much because you're going to fold the tire, but because it reduces rotating weight.
Zipp has even gone so far as to recommend tire pressures depending in your weight. You'll find these on the box.
The Zipp Tangente Clincher tire is fast to the wind, sticky to the ground, and possesses low rolling resistance.