Bridgestone Blizzak LM-25 4X4 is a winter tyre made in total of 3 sizes, ranging from R18 to R18 - this particular dimension is R19, which means it fits to a 19 inch/482.6mm diameter wheel. This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (255mm), which results in 127.5mm sidewall height. In 255/50 R19, there are 2 possible speed indexes for Bridgestone Blizzak LM-25 4X4 - "H","V", which are good for speeds up to 210, 240 km/h.