UHP Tire Breakaway Characteristics

[Vracer111]

Originally Posted by KendallH

Why would you go with a smaller tire than stock? The 215s from factory are a bit undersized IMO. And for a 7.5J wheel I would definitely go with a 235/40 or at least a 225/45.

Tread is actually wider than that of the stock 215/45-17 Primacy HP's (7.7" vs 7.5": for best tire and wheel responsiveness you want a tire tread width that closely matches the wheel width - too wide a tire tread width and the responsiveness suffers) and going to 205/45-17 on a 17x7.5 +40mm wheel you increase responsiveness more than stock along with having a more planted feeling due to actually lowering the CG of the car...much more suited to the car than 215/45-17 tires on 17x7 stock wheels.

Tire compound is what matters, not width...the compound is what gives you grip, width doesn't change the coefficient of friction, but it does play around with how the tire reacts to the road surface and the vehicle's stability. The Kumho Ecsta Sport LE has a nice sticky compound more akin to the Extreme performance tire category than the stock tires, it's more than enough for the car both in the wet and dry. Overall the car is more responsive and precise yet more stable at the same time when going to a Max performance category 205/45-17 tire on a 17x7.5 +40mm offset lightweight wheel...it's a win-win situation. Unnecessary unsprung weight is a bad thing...get 'skinny' sticky tires and refine the incredible chassis dynamics of the ZN6 with better stability, quicker reflexes, and better throttle sensitivity.

[wparsons]

Originally Posted by Vracer111

Tread is actually wider than that of the stock 215/45-17 Primacy HP's

My 205/50/17 snows are wider than the stock primacies as well, they run really narrow for a 215.