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. 275/40 R20 is 70mm wider than the narrowest dimension (205) and -10mm narrower than the widest one (265). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (275mm), which results in 110mm sidewall height. In 275/40 R20, there is only one possible speed index for Kumho WinterCraft WS71 - "W", which is good for speeds up to 270 km/h. In 275/40 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.