Nokian WR Snowproof is a winter tyre made in total of 59 sizes, ranging from R14 to R14 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/40 R18 is 60mm wider than the narrowest dimension (165) and -10mm narrower than the widest one (215). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (225mm), which results in 90mm sidewall height. In 225/40 R18, there is only one possible speed index for Nokian WR Snowproof - "V", which is good for speeds up to 240 km/h. In 225/40 R18, WR Snowproof usually competes against MS Plus 77, which is a tyre from Uniroyal with a rating of 55%, compared to 55% of the Nokian in question.
