Continental CrossContact RX is a summer tyre made in total of 36 sizes, ranging from R16 to R16 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (255mm), which results in 140.25mm sidewall height. In 255/55 R20, there are 2 possible speed indexes for Continental CrossContact RX - "W","Y", which are good for speeds up to 270, 300 km/h.