Hi, just bought 2008 Infiniti G37 Type P coupe, standard tyre size from my hazy memory is front 225/50/18 rear 245/45/18, but the car is set up with the 245/45/18's on the front and 235/50/18's on rear..It has the kn2000 lowering springs on it....seems odd to have the set up it has, any advise out there on why this set up, any suggestions... Cheer's 🤙🤙😎

 

stock tire overall diameter ranges from 26.6"-26.9" depending on wheel package.
the 245/45R18 is 26.7" which is fine.
the 235/50R18 is 27.3" and bigger what's offered from factory.
Between those two, its about a 2.2% difference. From a driveability stand point, it won't hurt the car. rule of staying under 3% different front-rear.

It could be that previous owner just needed something to ride on. it is better to have the taller tire in the rear. but i agree, very odd setup.

What wheels are you on? what's the width? If its wide enough, you could swap out those 235/50R18 for some 275/40R18. that;s go very nicely with your 245/45R18 fronts. Or square up on 245/45R18

 

They are standard 18' that came out of the factory..

 

I'm not sure which 18" wheels it is but form research, its seems that if you have the non-sport with 18", it might be 18x8.0 +43 square. The maximum approved tire size by ETRTO is a 245 section with. I would a 245/45R18 all around. its a pretty common size so replacing those rear 235 shouldn't be too hard.