235/40 R17 - Best summer tyres 2025 - market overview, tests, reviews

235/40 R17 doesn't belong to the most popular dimensions for summer tyres - there are 6 tyre models available, which can be compared to 155/60 R15, 170/60 R17, 160/60 R14. 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 R17, which means it fits to a 17 inch/431.8mm diameter wheel. The total circumference of the tyre is 1947.16 mm, which is very similar to 195/55 R16(1950.61 mm), 205/40 R18(1951.56 mm), 185/65 R15(1952.5 mm), 190/50 R17(1953.44 mm), 205/45 R17(1936.16 mm), 160/60 R17(1959.73 mm), 195/60 R15(1932.08 mm). There are multiple speed indexes available for summer tyres in 235/40 R17: W(270km/h), Y(300km/h). The same goes for weight indexes: 90, 94.