Hello everyone,

im going to fix an 18" wheels on my 997.1 C4S WB , so if im going with 18" what is the correct tire size ? from what i know is because its an all wheel drive car i have to put in mind the tire profile size between the front and rear to not face problems with traction control or drive shaft..

the current 19" goes with : 235/35 and 305/30

so for the 18" , should it be 235/45 and 305/40 ?:confused
or 235/40 and 305/35 ??

 

from audi days, the difference between front and rear circumference should be less than 3%, don't know if Porsche is different, but I would get as close to 0 as possible, shouldn't be too hard with all the tire availability these days, and they should be the same color...

 

The OEM recommendations are in your owner's manual under technical specs - separate page for C2 and for C4. Book says:

F 235/40-18
R 295/35-18