I neeed new tires. My G37s sedan has the stock 18s. I hear of folks putting 275s on the back.

What would the proper sizes be if I went with the 275s? Do I need to change the height, fronts....etc.

Many thanks.

 

You want to keep your new tire diameters within 3% or less of your stock size (to keep your speedo accurate), and the fronts should be as close as possible to the rear diameters (for ABS & traction control functions). Here's a good link to check sizing~
Tire Size Calculator - tire & wheel plus sizing

 

I wouldn't do that on 18s
I went with 255 instead of 245 on my 18s

 

Can 275/35r19 fit on the sedan in the rear?

 

Yes, no problem. The 19" sport wheels from the 370Z fit perfectly.