Overall handling was much better than what we expected and we also found the tires to communicate well, providing great feel. They had bite on entry and remained stable through each corner. Unfortunately, we didn't get to test the PZero tires in wet conditions, which was recommended by Pirelli. While dry performance was on par with the other tires, Tyson says the Corsas will shine in wet conditions. They are not suited well to drive in standing water, but in mist, light rain, or damp conditions, the tires will perform quite well as the tread design enhances the dissipation of water to prevent aquaplaning. This makes them especially appealing to the open-track enthusiast who drives his car to and from the track. They are even suitable for your daily driver, according to the manufacturer.
Next up was the GT, which exhibited different characteristics than the Cobra. The more softly sprung GT exhibited more body roll, but there was still a nice front-to-rear balance, and with each of the tires we noticed lap times that were about three seconds quicker on average than with the street BFG KD 265/45/18-inch rubber we rolled in on.
The Pirellis have plenty of traction from the get go, especially on entry. Turn-in was quick, and the nose of the GT followed the steering wheel quite well. We just needed a bit more power to maximize balance and performance. Even with the slight body roll, the tires remained stable and hooked up through the middle of each corner, though we experienced tire spin when exiting the tighter corners. We adjusted down to 27 psi, and this helped, but it didn't totally cure the problem. In the end, we attributed the wheelspin to a worn posi unit and a little too much body roll, which caused the vehicle's weight to unload the inside rear tire on exiting tighter corners.
Nitto NT01
According to Conrad Galamgam, a staff engineer at Nitto, "The NT01 is the pinnacle of Nitto Tire's technical excellence. It is a DOT-approved competition radial with an asymmetrical, non-directional tread pattern optimized for dry racing conditions. The design is our latest-generation road-race tire. The asymmetrical tread pattern allows you to rotate to all positions of the vehicle, and the large contact patch and increased lateral stiffness improves dry traction considerably (compared to NT555RII)."
From the start, we expected the NT01s to be quick, and they didn't disappoint. We first put them on the Cobra, and the speed with which we were carried around the course amazed us. The aggressive tread pattern provided mad grip, but the short, 6/32-inch tread depth was knocked down after about 15-20 laps, leaving us with a virtual "slick." We didn't mind, because we experienced race-car-like handling and the quickest lap times we've ever recorded on the 1.35-mile course--quicker even than a previously tested near-600-rwhp Ford GT and a borrowed M3. The only downside is that the NT01s are not the best choice for wet conditions. In fact, even though they are DOT-legal, they come with the caveat, "Not intended for highway use" on a sticker affixed to the tread.
The Cobra's brakes and the Nitto tires teamed up to give us the utmost confidence, even approaching 130 mph in the back straightaway, which leads to a hairy 90-degree left-hander. The harder we pushed, the quicker we went. We last tested the Nitto NT-555RII tires and recorded a best lap time of 1:25.68 (without the Roush/Alcon brakes and with about 30 less rear-wheel horsepower), but now we laid down a best of 1:20.29. That's a hell of an improvement on a track of this length. It's also 0.71 second faster than the aforementioned Ford GT supercar.