235/40 R18 - Best tyres 2025 - market overview, tests, reviews

235/40 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 (235mm), which means the sidewall height has 94 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 155/80 R13(1816.47 mm), 245/40 R17(1972.29 mm), 165/65 R13(1711.23 mm), 245/45 R20(2288.65 mm), 175/55 R15(1801.7 mm), 245/70 R17(2434.11 mm), 175/75 R16(2101.41 mm). You can find 235/40 R18 on 34 car models - mainly Mercedes-Benz, Maserati, Volkswagen, Audi, Porsche.