i bought some 350z rims .. 18"in size and inside the offsets are all labelled 30mm for all 4 rims ... I dont get this, if theyre the same size then why do they need to be labelled front and back ? ... maybe im missing something .. can someone please explain ?

 

Perhaps the F/R differ in width?

 

just like our "to-be" set! 8'' front, 8.5'' rear

 

on all 4 rims.. they all say 18x8 .... ??

 

The 350z comes with staggered tire size....245s in the rear and 235s in the front IIRC. If you get the same size tire there is no difference.

 

You have 4 front wheels, not a big deal. Use the same size tires all around and you'll be able to rotate the tires to extend tire life.

 

nope, I think not

some of the 350 18's are just like the G35 18s - all 4 are 18x8, but front tires are 225/45/18 and rear tires are 245/45/18. They are labeled front and rear because some morons might rotate teh 245/45s to the front.....

The rims themselves are exactly the same. My G35 18s also have front and rear stamped on the inside of the spokes.

 

^ Exactly what Irish said. I've got 4 G35 18's with 3 front and 1 rear.