275/65 R18 doesn't belong to the most popular dimensions for tyres - there are tyre models available, which can be compared to
325/30 R21,
155/60 R15,
155/65 R13. Let's break down the sizing - 65 is height of the tyre, which is calculated as 65% of the tyre width (275mm), which means the sidewall height has 178.75 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 mm, which is very similar to 215/70 R15
(2142.57 mm), 285/35 R22
(2382.27 mm), 225/35 R20
(2090.73 mm), 285/60 R18
(2510.76 mm), 225/50 R18
(2143.19 mm), 295/35 R20
(2244.67 mm), 225/60 R18
(2284.57 mm).
