Goodyear Regional Rhd Ii is a allround tyre made in total of 13 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/75 R17.5 is 225mm wider than the narrowest dimension (10) and -223mm narrower than the widest one (12). This tyre profile of 75 means the sidewall height of the tyre is 75% of the tyre width (235mm), which results in 176.25mm sidewall height. In 235/75 R17.5, there is only one possible speed index for Goodyear Regional Rhd Ii - "M", which is good for speeds up to km/h.