Pirelli P Zero Trofeo R is a summer tyre made in total of 4 sizes, ranging from R18 to R18 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (235mm), which results in 94mm sidewall height. In 235/40 R18, there is only one possible speed index for Pirelli P Zero Trofeo R - "Y", which is good for speeds up to 300 km/h. In 235/40 R18, P Zero Trofeo R usually competes against Ventus S1 evo3 K127, which is a tyre from Hankook with a rating of 74%, compared to 73% of the Pirelli in question.