255/40 R17 - Best summer tyres 2025 - market overview, tests, reviews

255/40 R17 doesn't belong to the most popular dimensions for summer tyres - there are 26 tyre models available, which can be compared to 165/65 R15, 165/65 R14, 155/70 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 R17, which means it fits to a 17 inch/431.8mm diameter wheel. The total circumference of the tyre is 1997.42 mm, which is very similar to 170/60 R17(1997.42 mm), 255/35 R18(1997.11 mm), 175/80 R14(1996.8 mm), 255/30 R19(1996.8 mm), 205/50 R17(2000.57 mm), 195/65 R15(1993.34 mm), 225/40 R18(2001.82 mm). There are multiple speed indexes available for summer tyres in 255/40 R17: V(240km/h), W(270km/h), Y(300km/h). The same goes for weight indexes: 94, 98. You can find 255/40 R17 on 1 car models - mainly Audi.