Riken 4X4 Road 701 is a tyre made in total of 50 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/60 R18 is 20mm wider than the narrowest dimension (205) and 60mm narrower than the widest one (285). 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 are 2 possible speed indexes for Riken 4X4 Road 701 - "H","V", which are good for speeds up to 210, 240 km/h.