Plus sizing is one of the easiest ways to achieve enhanced performance and improve the appearance of your vehicle. In the example above, a 15x7 wheel with a 205/65R-15 tire is considered the O.E. (original equipment) size. Converting to a plus 1 size would mean increasing the wheel diameter by 1" (16x7.5) and selecting an appropriate tire to fit (225/55R-16). Likewise, moving to a plus 2 fitment would result in a 17x8 wheel and a 245/45R-17 tire. It is important to note that although the wheel diameter is increasing, the overall diameter of the tire remains about the same.

A couple of things happen with the tire to increase performance when we begin to move into plus sizes. First, the tire is wider (section width) and therefore gives us a wider contact patch. Second, the sidewall becomes shorter (aspect ratio) and more rigid. The two added together give better lateral stability and increased steering response.