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 205/70 R15
(2098.58 mm), 275/40 R21
(2366.88 mm), 215/45 R17
(1964.44 mm), 275/55 R19
(2466.46 mm), 215/60 R17
(2167.07 mm), 285/35 R18
(2063.08 mm), 215/80 R15
(2277.65 mm).
