Pirelli P ZERO PZ4 305/40 R20

Pirelli P ZERO PZ4 is a summer tyre made in total of 700 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 305/40 R20 is 160mm wider than the narrowest dimension (145) and 30mm narrower than the widest one (335). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (305mm), which results in 122mm sidewall height.