215/35 R18 doesn't belong to the most popular dimensions for summer tyres - there are 8 tyre models available, which can be compared to 160/70 R17, 205/40 R17, 195/40 R17. Let's break down the sizing - 35 is height of the tyre, which is calculated as 35% of the tyre width (215mm), which means the sidewall height has 75.25 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 1909.15 mm, which is very similar to 175/65 R15(1911.66 mm), 205/55 R15(1905.38 mm), 195/65 R14(1913.54 mm), 185/55 R16(1916.06 mm), 205/50 R16(1920.77 mm), 215/40 R17(1896.89 mm), 185/60 R15(1894.38 mm). There are multiple speed indexes available for summer tyres in 215/35 R18: W(270km/h), Y(300km/h). The same goes for weight indexes: 84.