Firestone Roadhawk 2 is a summer tyre made in total of 93 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/35 R18 is 60mm wider than the narrowest dimension (195) and 40mm narrower than the widest one (295). This tyre profile of 35 means the sidewall height of the tyre is 35% of the tyre width (255mm), which results in 89.25mm sidewall height. In 255/35 R18, there is only one possible speed index for Firestone Roadhawk 2 - "Y", which is good for speeds up to 300 km/h. In 255/35 R18, Roadhawk 2 usually competes against Ecsta PS71, which is a tyre from Kumho with a rating of 76%, compared to 74% of the Firestone in question.