305's on a 12" wheel?
 

What do you guys think about trying to fit a 305/30/19 tire on a 19" x 12" wheel? It looks like it is a 1/2" out of the recommended range but I want to know practically how it might work.

Is the 305 you are using the standard tire size for the 4s/turbo? If so, I am running the standard tire 305 on a 2009 4S with the 12 inch GT3 rim and it is fine. Let me know if you want a photo.

Yes, they are the stock tires from a C4S. Iforged recommended a 315 but I hate to spend another $1k if I don't need to. Pics would be great if you have them handy.

305/30/zr19 came stock from porsche on my 2010 gt3 with 12" rims. so...

305 on a 12" wheel should definitely work. I have 305's on my 11" wheel and the tire is to big for my wheel. I bought the car with these tires on it, but I plan on running 305's or 315's when I get my new wheels that will be 12"

i run 305's on my 12" rears, no problem

315'S on a 12" wheel
 

With the 315'S on a 12' wheel any idea what the offset needs to be to completely center the tire? Obviously I am talking about the rear's. I am ordering a set of carbon fiber wheels (Carbon Concepts/Modular Concepts 01's) I want to show as much of the barrell as possible and I am afraid that if I do not get this 100% correct I will end up with a very expensive set of wheels that do not work on my 2003 C4S.

it should be fine, i'm running 305/30/19 in the rear for my hre's.

i have a 315 on a 12 inch wheel and it stretches..

i dont see how a 305 would fit on an aftermarket 12" 3 piece wheel