Michelin CrossClimate 2 SUV is a allround tyre made in total of 55 sizes, ranging from R17 to R17 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 245/45 R20 is 20mm wider than the narrowest dimension (225) and 30mm narrower than the widest one (275). 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.