Originally Posted by Agent-GHQ
Describe why the 255/275 is better than the OEM 245/265 "19 zcp, other than the cost.
For summer performance tires: Wider tires give a little more grip (#1 motivation in my opinion), slightly taller side-wall providing more compliance and pothole protection, 9/10" wheel widths are very well matched with 255/275 tire widths (good balance of proper wheel support and less stretch) and the taller/wider tires fill out the wheel wells nicely. I don't think going with 255/275 tires is as beneficial on the narrower 219m, 220m and 260m wheels which are only 8.5/9.5" wide.
For Winter tires: As stated above, the recommendation was driven by the fact that snows run narrower and can be difficult to install on the 9/10" wheels in OEM tire sizes, plus, the last time I checked, snows aren't available in OEM sizes. I recommend going with 18's in the winter and narrower is better for snow traction. I would however run 255/275 on ZCP wheels if I were to run snows on them.