I just bought c6 zo6 wheels for my 1999 convertible.
The wheels are 17x9.5 and 18x10.5.
What would be the best size tire for these wheels.
Anyway, to answer your original question, the stock C5 Zo6 tire size is 275/40/17 fr, 295/35/18 r. Those tires are a great improvement in traction and feel over stock C5 sizes. I run Eagle F1's in those sizes on my C5. A 285fr, 305r, will also fit on those wheels.