Michelin Pilot Sport 4 S is a summer tyre made in total of 250 sizes, ranging from R13 to R13 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 345/25 R21 is 120mm wider than the narrowest dimension (225) and -20mm narrower than the widest one (325). This tyre profile of 25 means the sidewall height of the tyre is 25% of the tyre width (345mm), which results in 86.25mm sidewall height. In
345/25 R21, Pilot Sport 4 S usually competes against
Ventus Evo, which is a tyre from
Hankook with a rating of 99%, compared to 96% of the
Michelin in question.