Nokian Seasonproof is a allround tyre made in total of 52 sizes, ranging from R14 to R14 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. 205/50 R17 is 40mm wider than the narrowest dimension (165) and 50mm narrower than the widest one (255). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (205mm), which results in 102.5mm sidewall height. In 205/50 R17, there is only one possible speed index for Nokian Seasonproof - "W", which is good for speeds up to 270 km/h. In 205/50 R17, Seasonproof usually competes against Multiseason 2, which is a tyre from Firestone with a rating of 58%, compared to 58% of the Nokian in question.