The sidewall for the NT01 has a high turn up which means that the plys that help form the tire’s bead that wrap around the bead are extended upward, about halfway up the sidewall. This gives the sidewall significant stiffness which helps hold the tires contact patch flat on the road under severe cornering loads. Unlike most passenger car tires that use polyester body plies in the carcass, the NT01 uses Rayon for its heat resistance. In addition, the NT01 uses two steel belts with an aramid cap ply that reduces growth at high speeds further reducing the running temperature. We ran a 245/40-18 in the front and a 275/40-18 in the rear. This is up from the stock 225/35-19 rear and 245-35-19 front tires. We decided to go down to an 18″ wheel due to the wider selection of less expensive tires available in 18″.
We mounted up the tires at our local America’s Tire store which is down the street from our shop.
Our fitment ended up being perfect with plenty of clearance for our new brake system which we will discuss in detail in our next article!
Since the function of our aero depends heavily on it, we carefully set the ride height as low as possible while still maintaining decent suspension geometry and wheel travel.
We believe that the 987 chassis has too much anti-squat geometry from the factory. That is why the cup cars are known to hop on corner exit. Lowering the car a lot reduces it some and we lowered the front pivot point of the rear trailing arm as much as we could go using the Tarett arms adjusting shims. We reduced the anti-squat percentage by about 50% over stock and we hope this cures the dreaded hop.