Bridgestone Turanza T005 is a summer tyre made in total of 350 sizes, ranging from R14 to R14 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 255/45 R20 is 100mm wider than the narrowest dimension (155) and 30mm narrower than the widest one (285). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (255mm), which results in 114.75mm sidewall height. In 255/45 R20, there is only one possible speed index for Bridgestone Turanza T005 - "W", which is good for speeds up to 270 km/h. In 255/45 R20, Turanza T005 usually competes against PremiumContact 6, which is a tyre from Continental with a rating of 87%, compared to 89% of the Bridgestone in question.