275/40 R19 doesn't belong to the most popular dimensions for summer tyres - there are 46 tyre models available, which can be compared to 205/70 R15, 195/60 R16, 185/55 R15. Let's break down the sizing - 40 is height of the tyre, which is calculated as 40% of the tyre width (275mm), which means the sidewall height has 110 mm. The wheel diameter is R19, which means it fits to a 19 inch/482.6mm diameter wheel. The total circumference of the tyre is 2207.28 mm, which is very similar to 245/50 R18(2206.03 mm), 245/45 R19(2208.85 mm), 225/60 R17(2204.77 mm), 215/75 R15(2210.11 mm), 245/55 R17(2203.2 mm), 245/40 R20(2211.68 mm), 285/30 R21(2212.94 mm). There are multiple speed indexes available for summer tyres in 275/40 R19: W(270km/h), Y(300km/h). The same goes for weight indexes: 101, 105. You can find 275/40 R19 on 4 car models - mainly Bentley, BMW, Volkswagen.