225/65 R18 doesn't belong to the most popular dimensions for summer tyres - there are 4 tyre models available, which can be compared to
155/60 R15,
170/60 R17,
160/60 R14. Let's break down the sizing - 65 is height of the tyre, which is calculated as 65% of the tyre width (225mm), which means the sidewall height has 146.25 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 2355.25 mm, which is very similar to 245/70 R16
(2354.31 mm), 245/65 R17
(2357.14 mm), 245/60 R18
(2359.96 mm), 315/30 R22
(2349.28 mm), 265/50 R19
(2348.65 mm), 265/70 R15
(2362.48 mm), 265/45 R20
(2345.2 mm). There are multiple speed indexes available for summer tyres in 225/65 R18: H
(210km/h), V
(240km/h). The same goes for weight indexes: 103, 107.
