155/85 R18 - Best summer tyres 2025 - market overview, tests, reviews

155/85 R18 doesn't belong to the most popular dimensions for summer tyres - there are 1 tyre models available, which can be compared to 155/60 R15, 170/60 R17, 160/60 R14. Let's break down the sizing - 85 is height of the tyre, which is calculated as 85% of the tyre width (155mm), which means the sidewall height has 131.75 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 2264.15 mm, which is very similar to 225/70 R16(2266.34 mm), 265/40 R20(2261.95 mm), 235/45 R20(2260.38 mm), 195/55 R20(2269.8 mm), 265/35 R21(2258.49 mm), 265/30 R22(2255.04 mm), 235/50 R19(2254.41 mm). There are multiple speed indexes available for summer tyres in 155/85 R18: M(km/h). The same goes for weight indexes: 115.