Don't disagree with any of the above but here's an interesting tidbit.
Looking at Tirerack, at many different mfrs of 255/45ZR18 tires, they show a Rim Width Range of 8-9.5" with a "design rim width." of 8.5".
Yet when you look at the 255/40ZR18, they show a Rim Width Range of 8.5-10" with a "design rim width." of 9".
So it appears that the aspect ratio, 45 vs 40 makes a difference as far as mfrs "design rim width" and acceptable range.
14 V6 auto, MCA, PP, BBK Shorties, MMD Hood Struts, Borla Touring A/B's, MAC ProChamber, aFe drop-in Filter
Lets not forget, an opinion is a judgment, viewpoint, or statement about matters commonly considered to be subjective.