Goodyear EfficientGrip SUV 4x4 is a summer tyre made in total of 0 sizes, ranging from R13 to R13 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/55 R18 is 225mm wider than the narrowest dimension () and -225mm narrower than the widest one (). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (225mm), which results in 123.75mm sidewall height.