275/35 R18 doesn't belong to the most popular dimensions for summer tyres - there are 21 tyre models available, which can be compared to 175/70 R13, 155/65 R13, 155/80 R13. Let's break down the sizing - 35 is height of the tyre, which is calculated as 35% of the tyre width (275mm), which means the sidewall height has 96.25 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 2041.09 mm, which is very similar to 160/60 R18(2039.52 mm), 235/30 R20(2038.89 mm), 285/25 R20(2043.61 mm), 215/45 R18(2044.23 mm), 225/60 R15(2045.18 mm), 185/80 R14(2047.06 mm), 180/60 R17(2035.12 mm). There are multiple speed indexes available for summer tyres in 275/35 R18: W(270km/h), Y(300km/h). The same goes for weight indexes: 95, 99.