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. 305/30 R21 is 80mm wider than the narrowest dimension (225) and 20mm narrower than the widest one (325). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (305mm), which results in 91.5mm sidewall height. In
305/30 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.