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 205/55 R19
(2224.56 mm), 275/35 R20
(2200.69 mm), 215/35 R18
(1909.15 mm), 275/45 R19
(2293.68 mm), 215/55 R16
(2019.73 mm), 275/70 R16
(2486.26 mm), 215/70 R15
(2142.57 mm).
