Firestone Firehawk SZ90 225/45 R18

Firestone Firehawk SZ90 is a summer tyre made in total of 41 sizes, ranging from R13 to R13 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/45 R18 is 30mm wider than the narrowest dimension (195) and 30mm narrower than the widest one (255). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (225mm), which results in 101.25mm sidewall height.