Gripmax SureGrip Pro Winter 315/40 R21

Gripmax SureGrip Pro Winter is a winter tyre made in total of 35 sizes, ranging from R17 to R17 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 315/40 R21 is 140mm wider than the narrowest dimension (175) and 20mm narrower than the widest one (335). 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.