Hankook ION Evo is a summer tyre made in total of 24 sizes, ranging from R13 to R13 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 285/35 R21 is 70mm wider than the narrowest dimension (215) and 20mm narrower than the widest one (305). This tyre profile of 35 means the sidewall height of the tyre is 35% of the tyre width (285mm), which results in 99.75mm sidewall height. In 285/35 R21, there is only one possible speed index for Hankook ION Evo - "Y", which is good for speeds up to 300 km/h.