Nokian Powerproof is a summer tyre made in total of 53 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/45 R18 is 20mm wider than the narrowest dimension (205) and 50mm narrower than the widest one (275). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (225mm), which results in 101.25mm sidewall height. In 225/45 R18, there is only one possible speed index for Nokian Powerproof - "Y", which is good for speeds up to 300 km/h. In 225/45 R18, Powerproof usually competes against Roadhawk, which is a tyre from Firestone with a rating of 57%, compared to 52% of the Nokian in question. Latest test in 225/45 R18 was held by AutoMotorSport in 2020, where Powerproof received rating "Good" and finished on the 7. place. It was tested on a BMW 3 series.
