255/55 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 - 55 is height of the tyre, which is calculated as 55% of the tyre width (255mm), which means the sidewall height has 140.25 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 255/70 R18
(2557.88 mm), 195/55 R20
(2269.8 mm), 265/35 R21
(2258.49 mm), 195/70 R15
(2054.6 mm), 265/45 R21
(2425 mm), 205/45 R16
(1856.37 mm), 265/70 R16
(2442.27 mm).
