Cooper Discoverer STT PRO 305/55 R20

Cooper Discoverer STT PRO is a tyre made in total of 45 sizes, ranging from R13 to R13 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 305/55 R20 is 274mm wider than the narrowest dimension (31) and 0mm narrower than the widest one (305). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (305mm), which results in 167.75mm sidewall height.