I bought my 2003 G35 coupe 1 week ago today. I noticed a lot of road noise at slow speeds and some shaking at high speeds. I thought it was just bad tires on the front. The previous owner put Discount tires on the front. 225/50 17". The tread was fine, but tons of road noise. I brought it into Discount tire today to have them look at the balance and maybe rotate the fronts. The started to rotate them and noticed the front passenger side would not mount flush on the lugs.

Whoever mounted the tires last time, put a 225/50/17 on the rear rim and mounted it on the front. Then mounted the 235/50/17 rear tire on the front rim and put it on the back.

Problem solved runs great now.

 

I just got an '03 coupe recently too. Glad to hear the problem got fixed before any damage was done.

 

Different width rims on the 17" G35 Coupe. 7.5 on fronts and 8 on rears.