Barum Polaris 3 is a winter tyre made in total of 65 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 275/45 R20 is 140mm wider than the narrowest dimension (135) and -30mm narrower than the widest one (245). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (275mm), which results in 123.75mm sidewall height. In 275/45 R20, Polaris 3 usually competes against Radial Champiro WinterPro 2, which is a tyre from GT with a rating of 60%, compared to 0% of the Barum in question.