Michelin Alpin A4 is a winter tyre made in total of 35 sizes, ranging from R14 to R14 - this particular dimension is R15, which means it fits to a 15 inch/381mm diameter wheel. 185/55 R15 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 R15, there are 2 possible speed indexes for Michelin Alpin A4 - "T","H", which are good for speeds up to 190, 210 km/h. In 185/55 R15, Alpin A4 usually competes against Blizzak LM-005, which is a tyre from Bridgestone with a rating of 87%, compared to 0% of the Michelin in question.
