Pirelli WINTER SOTTOZERO Serie III is a winter tyre made in total of 228 sizes, ranging from R16 to R16 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 255/45 R20 is 50mm wider than the narrowest dimension (205) and 100mm narrower than the widest one (355). 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. In 255/45 R20, there is only one possible speed index for Pirelli WINTER SOTTOZERO Serie III - "V", which is good for speeds up to 240 km/h. In 255/45 R20, WINTER SOTTOZERO Serie III usually competes against SP Sport MAXX RT2, which is a tyre from Dunlop with a rating of 72%, compared to 0% of the Pirelli in question.