285/45 R18 doesn't belong to the most popular dimensions for allround tyres - there are 0 tyre models available, which can be compared to 155/60 R15, 170/60 R17, 160/60 R14. Let's break down the sizing - 45 is height of the tyre, which is calculated as 45% of the tyre width (285mm), which means the sidewall height has 128.25 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 2242.15 mm, which is very similar to 235/60 R17(2242.47 mm), 205/75 R16(2242.78 mm), 295/35 R20(2244.67 mm), 255/45 R19(2237.13 mm), 255/40 R20(2236.81 mm), 235/65 R16(2236.5 mm), 235/55 R18(2248.44 mm).