Dunlop SP MAX Roadsmart II is a winter tyre made in total of 13 sizes, ranging from R17 to R17 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. 190/50 R17 is 80mm wider than the narrowest dimension (110) and 10mm narrower than the widest one (200). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (190mm), which results in 95mm sidewall height. In 190/50 R17, there is only one possible speed index for Dunlop SP MAX Roadsmart II - "W", which is good for speeds up to 270 km/h.