General Altimax Sport 255/40 R18

General Altimax Sport is a summer tyre made in total of 20 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/40 R18 is 60mm wider than the narrowest dimension (195) and -10mm narrower than the widest one (245). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (255mm), which results in 102mm sidewall height.