Continental ContiWinterContact TS 830P is a winter tyre made in total of 101 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/50 R18 is 30mm wider than the narrowest dimension (195) and 30mm narrower than the widest one (255). 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 R18, there are 2 possible speed indexes for Continental ContiWinterContact TS 830P - "H","V", which are good for speeds up to 210, 240 km/h.