Nokian Powerproof 1 is a summer tyre made in total of 54 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/40 R18 is 20mm wider than the narrowest dimension (205) and 50mm narrower than the widest one (275). 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 Powerproof 1 - "Y", which is good for speeds up to 300 km/h. In 225/40 R18, Powerproof 1 usually competes against Potenza Sport, which is a tyre from Bridgestone with a rating of 87%, compared to 62% of the Nokian in question. Latest test in 225/40 R18 was held by ADAC in 2025, where Powerproof 1 received rating "Satisfactory" and finished on the 14. place. It was tested on a VW Golf.
