Originally Posted by RBfastback

I may be looking too far into this but maybe someone can enlighten me.
For rear Nismo wheels changing the stock 285/35/19 over to a 305 everyone says to go with 305/30/19 but that doesn't make sense if ur doing it for traction because u may gain about .79 inch wider but your loosing overall diameter -2.04 inch or -2.4% circum. so it's a wash from what I gained going wider.
but 305/35/19 u gain .79 wide and gain 1.73 inch or 2.1% circum. and that's less of a difference or change then oem size so your speedo would technically be more accurate with the 305/35/19 even tho it's a small difference but that means slightly more meat.

all the percentages are less of a change for 35 series tires