Dunlop SP Sport Maxx RT is a summer tyre made in total of 100 sizes, ranging from R16 to R16 - 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 (205mm), which results in 82mm sidewall height. In 205/40 R18, there are 2 possible speed indexes for Dunlop SP Sport Maxx RT - "W","Y", which are good for speeds up to 270, 300 km/h. In 205/40 R18, SP Sport Maxx RT usually competes against P ZERO, which is a tyre from Pirelli with a rating of 61%, compared to 70% of the Dunlop in question.