GT Radial Champiro WinterPro 2 is a winter tyre made in total of 43 sizes, ranging from R13 to R13 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 245/45 R18 is 90mm wider than the narrowest dimension (155) and 0mm narrower than the widest one (245). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (245mm), which results in 110.25mm sidewall height. In 245/45 R18, Radial Champiro WinterPro 2 usually competes against WinTech, which is a tyre from Viking with a rating of 58%, compared to 60% of the GT in question.