Continental Htr2 is a summer tyre made in total of 14 sizes, ranging from R17 to R17 - this particular dimension is R23, which means it fits to a 23 inch/584.2mm diameter wheel. 385/55 R22.5 is 180mm wider than the narrowest dimension (205) and 0mm narrower than the widest one (385). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (385mm), which results in 211.75mm sidewall height. In 385/55 R22.5, there is only one possible speed index for Continental Htr2 - "K", which is good for speeds up to km/h.