Michelin Alpin 5 315/30 R21

Michelin Alpin 5 is a winter tyre made in total of 92 sizes, ranging from R15 to R15 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 315/30 R21 is 130mm wider than the narrowest dimension (185) and 0mm narrower than the widest one (315). 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.