Continental ContiWinterContact TS 810S is a winter tyre made in total of 27 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 245/40 R18 is 70mm wider than the narrowest dimension (175) and 0mm narrower than the widest one (245). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (245mm), which results in 98mm sidewall height. In 245/40 R18, there are 2 possible speed indexes for Continental ContiWinterContact TS 810S - "V","W", which are good for speeds up to 240, 270 km/h.