The Pirelli PZero Corsa tires are designed to work well in damp or wet conditions; we'll try that at a later date.
In Conclusion
We're pleased to say the results were positive with each of the tires tested. The only glitches of the day were a couple of cracked sockets and a broken gas pedal in the Cobra, but even that didn't stop us.
At the limit, the Nitto NT01s outperformed the other two, but that might have changed if the track had been wet. If you're after all-out grip, the NT01 is a hot lick, but it's a dry-weather tire and the compound is super-soft, so its life expectancy is not equal to the Pirelli or Toyo models tested. And that's something to consider if you're going to run open track or autocross on a regular basis, or if you may get caught in the wet.
Both the Pirellis and the Toyos offered just about equal performance. Again, they provided lap times in our Cobra that would put you ahead of cars costing thousands more at your next driving event. And who wouldn't get a thrill out of blowing past a C-6 Vette or Porsche Carrera in an ordinary, mass produced, blue-collar Mustang?
Ultimately, it's up to you to pick a set of tires that will be best suited for your car and your driving style. You won't be disappointed with any of these, but you may have trouble wiping the grin off your face after you experience such impressive cornering.
THE PLAYERS
Nitto
Maximum grip came from the sticky 275/35ZR18-inch Nitto NT01 tires. The aggressive tread pattern kept lots of rubber on the road, which translated into race car-like traction and cornering speeds. The NT01 is graded as a DOT tire, but is not recommended for highway use. It's also the spec tire for the American V8 Supercar Series.
Pirelli
"The compound [of the PZero Corsa] has a true competition wear rating of 60, which is quite low for a road tire," says Peter Tyson of Pirelli. "It's almost impossible to say how long they would last [on the street], but perhaps half or one-third that of a normal tire. The compound is comparable to a hard-compound, endurance-racing tire. The pattern, being asymmetrical, means it has fewer cuts in the tread on the outer shell than the inner shell to maximize the level of tires that stays on the ground in a corner."
Toyo
"At its full tread depth of 8/32 inch, the RA-1 provides wet traction, but when shaved to 4/32 inch, hang on as your dry lap times drop," explains our source at Toyo. The RA-1s feature a directional tread pattern, but according to Toyo, this designation is only applicable in wet conditions for water dispersion. When the road or track is dry, the direction of rotation is not important.