215/45 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 - 45 is height of the tyre, which is calculated as 45% of the tyre width (215mm), which means the sidewall height has 96.75 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 195/60 R16
(2011.88 mm), 265/40 R19
(2182.15 mm), 195/80 R15
(2177.12 mm), 265/55 R19
(2431.91 mm), 205/50 R16
(1920.77 mm), 275/30 R19
(2034.5 mm), 205/65 R15
(2034.18 mm).
