245/55 R18 doesn't belong to the most popular dimensions for tyres - there are tyre models available, which can be compared to
325/30 R21,
155/60 R15,
155/65 R13. Let's break down the sizing - 55 is height of the tyre, which is calculated as 55% of the tyre width (245mm), which means the sidewall height has 134.75 mm. The wheel diameter is R18, which means it fits to a 18 inch/457.2mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 285/35 R18
(2063.08 mm), 215/85 R16
(2425 mm), 285/45 R19
(2321.95 mm), 225/45 R19
(2152.31 mm), 295/30 R19
(2072.19 mm), 225/60 R15
(2045.18 mm), 295/45 R20
(2430.02 mm).
