Bridgestone Turanza 6 is a summer tyre made in total of 115 sizes, ranging from R16 to R16 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 245/45 R20 is 50mm wider than the narrowest dimension (195) and 40mm narrower than the widest one (285). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (245mm), which results in 110.25mm sidewall height. In 245/45 R20, there are 2 possible speed indexes for Bridgestone Turanza 6 - "V","Y", which are good for speeds up to 240, 300 km/h.