Kumho WinterCraft WS71 is a winter tyre made in total of 64 sizes, ranging from R15 to R15 - 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 10mm narrower than the widest one (265). 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 Kumho WinterCraft WS71 - "V", which is good for speeds up to 240 km/h. In 255/45 R20, WinterCraft WS71 usually competes against WR SUV 4, which is a tyre from Nokian with a rating of 26%, compared to 0% of the Kumho in question.