255/40 R18 - Best tyres 2025 - market overview, tests, reviews

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 205/55 R16(1985.17 mm), 275/35 R18(2041.09 mm), 205/75 R16(2242.78 mm), 275/40 R22(2446.67 mm), 215/45 R18(2044.23 mm), 275/65 R17(2479.66 mm), 215/65 R15(2075.02 mm). You can find 255/40 R18 on 14 car models - mainly Mercedes-Benz, BMW, Audi, Ferrari, Jaguar.