Pirelli P ZERO Nero GT 255/30 R20

Pirelli P ZERO Nero GT is a summer tyre made in total of 46 sizes, ranging from R16 to R16 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 255/30 R20 is 60mm wider than the narrowest dimension (195) and 50mm narrower than the widest one (305). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (255mm), which results in 76.5mm sidewall height.