I have an infinity g35 coupe (brembo) and I would like to know if the wheel size is the same in front and in back (18x8.. ?).
If I put the original tires on my summer wheels (18x9) will the 225-40-18 will fit ?

 

welcome... OEM 18's are 18X8 all around, but have staggered tire fitments... plus there's a neat little bolt on the hubs that prevents you from putting the rear wheels on the front... and they're labeled too... 225/40/18 probably wont fit on your 18x9, if anything it will be stretched alot. i personally wouldn't do it...

 

putting stock tire sizes on a 18x9 rim would be way to streched and not safe at all

 

so what I should put in front ? 235 ?

 

235/40-18 would be close, but still 2.2% too small, so your speedo would read 2% higher than what you are actually doing. 235/45-18 is 1.4% too big.

BTW, it's "Infiniti," not Infinity.