Avon ZX7 275/40 R20

Avon ZX7 is a summer tyre made in total of 67 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 275/40 R20 is 60mm wider than the narrowest dimension (215) and 20mm narrower than the widest one (295). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (275mm), which results in 110mm sidewall height.