Nokian Powerproof is a summer tyre made in total of 53 sizes, ranging from R17 to R17 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. 225/50 R17 is 20mm wider than the narrowest dimension (205) and 50mm narrower than the widest one (275). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (225mm), which results in 112.5mm sidewall height. In 225/50 R17, there are 2 possible speed indexes for Nokian Powerproof - "W","Y", which are good for speeds up to 270, 300 km/h. In 225/50 R17, Powerproof usually competes against Roadhawk, which is a tyre from Firestone with a rating of 57%, compared to 52% of the Nokian in question.
