Hankook Winter I-Cept iOn X 255/40 R21

Hankook Winter I-Cept iOn X is a winter tyre made in total of 23 sizes, ranging from R18 to R18 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 255/40 R21 is 20mm wider than the narrowest dimension (235) and 40mm narrower than the widest one (295). 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.