GT Radial Champiro HPY 255/55 R18

GT Radial Champiro HPY is a summer tyre made in total of 9 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/55 R18 is 40mm wider than the narrowest dimension (215) and -20mm narrower than the widest one (235). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (255mm), which results in 140.25mm sidewall height.