So I want to get some tires. I'd like to go with 40 series but I am seeing some issues that might freak out the VDC. Here's the specs:

STOCK DIAMETERS
Front: 25.97
Rear: 26.68
Relative diameter dif of .71 (this ratio needs to be maintained or VDC could freak)

40 SERIES TIRE
Front: 25.40 (235/40/R18)
Rear: 26.03 (255/40R18)
Relative diameter dif of .63 (.08 difference)


Now if I wanted to keep VDC happy I could just put wider same profile tires on the car, but I'd rather get the lower profile than wider. So really I guess I have to stick with stock if the .08 difference will freak out the VDC. Here's the wider's specs....

45 SERIES TIRE
Front: 26.33 (235/45/R18)
Rear: 27.04 (255/45R18)
Relative diameter dif of .71


Anyone have any tips or issues? Thanks.

 

I've seen it posted that the difference is supposed to be between 0.5 and 0.75. At the same time, a number of people (especially those who go with NISMO wheels) are using 245/40/18 and 275/40/18 and if I remember correctly the difference there is 0.8". That is the recommended sizes and nobody reports VDC problems so that leads me to believe the 0.5 to 0.75 claim is not true.

Your best bet is to post in the Wheels, Tires, Brakes, Suspension forum and you're bound to find somebody that tried any combination you can think of.