Michelin Pilot Sport 5 is a summer tyre made in total of 71 sizes, ranging from R13 to R13 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 255/40 R21 is 60mm wider than the narrowest dimension (195) and 20mm narrower than the widest one (275). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (255mm), which results in 102mm sidewall height. In
255/40 R21, Pilot Sport 5 usually competes against
Eagle F1 Asymmetric 6, which is a tyre from
Goodyear with a rating of 94%, compared to 94% of the
Michelin in question.