245/30 R20 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 - 30 is height of the tyre, which is calculated as 30% of the tyre width (245mm), which means the sidewall height has 73.5 mm. The wheel diameter is R20, which means it fits to a 20 inch/508mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 235/50 R18
(2174.61 mm), 235/60 R18
(2322.27 mm), 155/65 R14
(1750.18 mm), 245/35 R19
(2054.92 mm), 160/70 R17
(2060.26 mm), 245/45 R17
(2049.26 mm), 165/80 R13
(1866.73 mm).
