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. 275/35 R21 is 40mm wider than the narrowest dimension (235) and 20mm narrower than the widest one (295). This tyre profile of 35 means the sidewall height of the tyre is 35% of the tyre width (275mm), which results in 96.25mm sidewall height. In 275/35 R21, there is only one possible speed index for Hankook Winter I-Cept iOn X - "V", which is good for speeds up to 240 km/h.