Gt Radial Fe2 Suv is a tyre made in total of 12 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/55 R18 is 20mm wider than the narrowest dimension (215) and 0mm narrower than the widest one (235). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (235mm), which results in 129.25mm sidewall height. In 235/55 R18, there is only one possible speed index for Gt Radial Fe2 Suv - "V", which is good for speeds up to 240 km/h.