Michelin PILOT ALPIN 5 is a winter tyre made in total of 102 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/45 R18 is 30mm wider than the narrowest dimension (205) and 50mm narrower than the widest one (285). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (235mm), which results in 105.75mm sidewall height. In 235/45 R18, there is only one possible speed index for Michelin PILOT ALPIN 5 - "V", which is good for speeds up to 240 km/h. In 235/45 R18, PILOT ALPIN 5 usually competes against UltraGrip Performance+, which is a tyre from GoodYear with a rating of 87%, compared to 99% of the Michelin in question.