215/40 R17 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 (215mm), which means the sidewall height has 86 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 mm, which is very similar to 275/30 R19(2034.5 mm), 205/65 R15(2034.18 mm), 275/40 R19(2207.28 mm), 215/45 R16(1884.64 mm), 275/50 R20(2459.87 mm), 215/60 R16(2087.27 mm), 285/30 R20(2133.14 mm). You can find 215/40 R17 on 13 car models - mainly Seat, Skoda, Alfa Romeo, Audi, Ford.