Nokian Line is a summer tyre made in total of 53 sizes, ranging from R14 to R14 - this particular dimension is R15, which means it fits to a 15 inch/381mm diameter wheel. 185/55 R15 is 10mm wider than the narrowest dimension (175) and 40mm narrower than the widest one (225). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (185mm), which results in 101.75mm sidewall height. In 185/55 R15, there is only one possible speed index for Nokian Line - "H", which is good for speeds up to 210 km/h. In 185/55 R15, Line usually competes against Roadhawk, which is a tyre from Firestone with a rating of 59%, compared to 0% of the Nokian in question.