I have a 2008 G35Xs with 18 x 7.5 oem sport wheels and the correct tire size is 225/50/18.
I picked up some barely used Blizzak LM-60 snow tires off of ebay. The sizes are: (2) 225/50/18 and (2) 245/45/18

The ad originally said (4) 225/50/18 which is the correct size to the car. I was going to send them back, but thought I would check and see if I could run the 245/45/18's on the rear and the 225/50/18's up front. all tires would be mounted on the 18 x 7.5 oem rims.

Will this staggered tire fitment mess up my differential or VDC?

I ran a calculator and this is the results: They are not too far off...


Diameter 682.2mm 677.7mm
Circumference 2143.2mm 2129.1mm
Speedo error 0% 0.66%
Reading at 30mph 30mph 30.2mph
Reading at 60mph 60mph 60.4mph
Ride height gain 0mm -2.25mm
Arch gap loss 0mm -2.25mm

 

There is two tenths of an inch between the sizes. You will want to ask Infiniti what the tolerance is for diameter. Some cars have zero tolerance and it's a must that they match front/rear. You're better off with a narrower tire out back for winter anyway, so I would look for a matched set in the same size.