Michelin Alpin A4 is a winter tyre made in total of 35 sizes, ranging from R14 to R14 - this particular dimension is R16, which means it fits to a 16 inch/406.4mm diameter wheel. 185/55 R16 is 20mm wider than the narrowest dimension (165) and 40mm narrower than the widest one (225). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (185mm), which results in 101.75mm sidewall height. In 185/55 R16, there is only one possible speed index for Michelin Alpin A4 - "H", which is good for speeds up to 210 km/h.
