Megatronss

Appreciate all the help. For me I think the Michelin's are out....

sounds like Ike I can't really go wrong though with either the Toyo's or the Nitto's for what I want. Kinda leaning toward the R888's.....

DanMan35

What does the ZR in the tire description mean? And how do you identify if you have run flats or not?

I have:

Front: 285/30ZR/19
Rear: 335/25ZR/20

Is anyone who is modding their Z06 running 20's or should I be switching to a smaller wheel size soon?

AzDave47

What brand/model tire? If Michelin and they have ZP on the side they are run flats, Goodyear uses EMT for run-flats. The ZR is an overall speed rating for radial tire, but there is probably a more specific W, Y or (Y) code that is more specific regarding speed rating of the tire.
W=168 MPH sustained
Y= 186 MPH sustained and
(Y) meens over 186 MPH sustained.

The Z comes from the factory with either Y or (Y) rated tires.

Tire size choice is limited with to 20" rears and somewhat with the 19" front. Even 19" rear somewhat limits tire size choice however if you have the CCB brakes many 18" rims will not clear them (fronts perdominently), some will.

Tire Rack web site has good info on reading all the codes and markings on the sidewall of the tire including date of manufacture and traction/treadwear and other info.