Kumho Ecsta PS91 255/40 R18

Kumho Ecsta PS91 is a summer tyre made in total of 50 sizes, ranging from R18 to R18 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/40 R18 is 30mm wider than the narrowest dimension (225) and 20mm narrower than the widest one (275). 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.