Continental Wintercontact Ts860S is a winter tyre made in total of 48 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/55 R18 is 30mm wider than the narrowest dimension (195) and -10mm narrower than the widest one (215). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (225mm), which results in 123.75mm sidewall height. In 225/55 R18, there is only one possible speed index for Continental Wintercontact Ts860S - "H", which is good for speeds up to 210 km/h.