Michelin Primacy 4 315/30 R21

Michelin Primacy 4 is a summer tyre made in total of 368 sizes, ranging from R14 to R14 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 315/30 R21 is 160mm wider than the narrowest dimension (155) and -10mm narrower than the widest one (305). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (315mm), which results in 94.5mm sidewall height.