Michelin Primacy 5 is a summer tyre made in total of 79 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/50 R18 is 40mm wider than the narrowest dimension (195) and 10mm narrower than the widest one (245). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (235mm), which results in 117.5mm sidewall height. In 235/50 R18, there are 2 possible speed indexes for Michelin Primacy 5 - "V","Y", which are good for speeds up to 240, 300 km/h. In 235/50 R18, Primacy 5 usually competes against PremiumContact 6, which is a tyre from Continental with a rating of %, compared to 90% of the Michelin in question.