305/30 R20 doesn't belong to the most popular dimensions for allround tyres - there are 0 tyre models available, which can be compared to
155/60 R15,
170/60 R17,
160/60 R14. Let's break down the sizing - 30 is height of the tyre, which is calculated as 30% of the tyre width (305mm), which means the sidewall height has 91.5 mm. The wheel diameter is R20, which means it fits to a 20 inch/508mm diameter wheel. The total circumference of the tyre is 2170.84 mm, which is very similar to 235/55 R17
(2168.64 mm), 215/60 R17
(2167.07 mm), 235/50 R18
(2174.61 mm), 265/30 R21
(2175.24 mm), 295/35 R19
(2164.87 mm), 195/80 R15
(2177.12 mm), 265/35 R20
(2178.69 mm).
