Nankang SP-9 Cross Sport 225/55 R18

Nankang SP-9 Cross Sport is a tyre made in total of 28 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/55 R18 is 10mm wider than the narrowest dimension (215) and 90mm narrower than the widest one (315). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (225mm), which results in 123.75mm sidewall height.