Sumitomo Bc100 255/45 R20

Sumitomo Bc100 is a tyre made in total of 137 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 255/45 R20 is 110mm wider than the narrowest dimension (145) and 0mm narrower than the widest one (255). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (255mm), which results in 114.75mm sidewall height.