Continental UltraContact is a summer tyre made in total of 80 sizes, ranging from R14 to R14 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. 225/50 R17 is 70mm wider than the narrowest dimension (155) and -30mm narrower than the widest one (195). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (225mm), which results in 112.5mm sidewall height. In 225/50 R17, there is only one possible speed index for Continental UltraContact - "V", which is good for speeds up to 240 km/h.