Michelin Primacy 4 is a summer tyre made in total of 239 sizes, ranging from R15 to R15 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/55 R18 is 70mm wider than the narrowest dimension (165) and 20mm narrower than the widest one (255). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (235mm), which results in 129.25mm sidewall height. In 235/55 R18, there are 2 possible speed indexes for Michelin Primacy 4 - "W","V", which are good for speeds up to 270, 240 km/h. In 235/55 R18, Primacy 4 usually competes against PremiumContact 6, which is a tyre from Continental with a rating of 83%, compared to 82% of the Michelin in question. Latest test in 235/55 R18 was held by Tyre Reviews in 2021, where Primacy 4 received rating "Test winner" and finished on the 1. place. It was tested on a .
