Nankang SP-9 Cross Sport is a tyre made in total of 27 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/65 R18 is 20mm wider than the narrowest dimension (215) and 80mm narrower than the widest one (315). This tyre profile of 65 means the sidewall height of the tyre is 65% of the tyre width (235mm), which results in 152.75mm sidewall height. In 235/65 R18, there is only one possible speed index for Nankang SP-9 Cross Sport - "", which is good for speeds up to km/h.