Hankook H750 Kinergy 4S2 is a allround tyre made in total of 55 sizes, ranging from R14 to R14 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/60 R18 is 60mm wider than the narrowest dimension (165) and -30mm narrower than the widest one (195). This tyre profile of 60 means the sidewall height of the tyre is 60% of the tyre width (225mm), which results in 135mm sidewall height. In 225/60 R18, there is only one possible speed index for Hankook H750 Kinergy 4S2 - "W", which is good for speeds up to 270 km/h.