Nexen Winguard Snow G3 WH21 is a winter tyre made in total of 64 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 245/45 R20 is 100mm wider than the narrowest dimension (145) and -20mm narrower than the widest one (225). 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 R20, Winguard Snow G3 WH21 usually competes against Polaris 5, which is a tyre from Barum with a rating of 63%, compared to 60% of the Nexen in question.