Bridgestone Blizzak 6 305/40 R20

Bridgestone Blizzak 6 is a winter tyre made in total of 194 sizes, ranging from R16 to R16 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 305/40 R20 is 120mm wider than the narrowest dimension (185) and 20mm narrower than the widest one (325). 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.