Michelin Pilot Sport EV 315/40 R21

Michelin Pilot Sport EV is a summer tyre made in total of 90 sizes, ranging from R19 to R19 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 315/40 R21 is 90mm wider than the narrowest dimension (225) and 0mm narrower than the widest one (315). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (315mm), which results in 126mm sidewall height.