Bridgestone Potenza S001 is a summer tyre made in total of 151 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 50mm wider than the narrowest dimension (205) and 50mm narrower than the widest one (305). 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 Bridgestone Potenza S001 - "Y", which is good for speeds up to 300 km/h. In 255/35 R18, Potenza S001 usually competes against SP Sport MAXX RT2, which is a tyre from Dunlop with a rating of 79%, compared to 58% of the Bridgestone in question.