225/30 R18 doesn't belong to the most popular dimensions for winter 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 - 30 is height of the tyre, which is calculated as 30% of the tyre width (225mm), which means the sidewall height has 67.5 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 195/55 R16
(1950.61 mm), 265/35 R19
(2098.9 mm), 195/70 R14
(1974.81 mm), 265/45 R18
(2185.61 mm), 205/40 R18
(1951.56 mm), 265/65 R18
(2518.61 mm), 205/55 R17
(2064.97 mm).
