255/40 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 - 40 is height of the tyre, which is calculated as 40% of the tyre width (255mm), which means the sidewall height has 102 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 255/65 R17
(2397.98 mm), 195/50 R16
(1889.35 mm), 265/35 R18
(2019.1 mm), 195/65 R15
(1993.34 mm), 265/40 R21
(2341.74 mm), 200/60 R17
(2110.52 mm), 265/65 R17
(2438.82 mm). You can find 255/40 R18 on 14 car models - mainly .
