The factory 255's are a perfect fit for the rear factory wheels, however the 275's will fit fine on the rears, as stated above, the tire will stick past the wheel a bit, but nothing that will affect the dynamics much.
The fronts could also run a wider size, a 245 will fit great. However when changing the widths of the tires you will also be changing the sidewall size as well. So basically for a 255/35/19 (oem size rear) the sidewall measures 3.5" whereas on a 275/35/19, the sidewall measures 3.8". In the case of the front tires, the factory size is a 225/40/19 the sidewall measures 3.5" and on a 245/40/19 the sidewall measures 3.9".
If you look at the numbers you can see why KIA decided to use those tire sizes, the sidewall measures the same and maintains a leveled ride height.
That's exactly what I thought when I saw how far out those rims and spokes are protruding. This isn't Ben Hur where we are trying to tear up the competition's wheels ferpetesakes! And curbs are waiting eeeverywhere, like an ambush, just for that moment when you don't see one of them. I didn't appreciate before the Stinger just how vulnerable these high aspect ratio tires make the rims.
