Dunlop SP Sport Maxx RT is a summer tyre made in total of 100 sizes, ranging from R16 to R16 - this particular dimension is R19, which means it fits to a 19 inch/482.6mm diameter wheel. 255/30 R19 is 50mm wider than the narrowest dimension (205) and 80mm narrower than the widest one (335). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (255mm), which results in 76.5mm sidewall height. In 255/30 R19, there is only one possible speed index for Dunlop SP Sport Maxx RT - "Y", which is good for speeds up to 300 km/h. In 255/30 R19, 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.