225/40 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 - 40 is height of the tyre, which is calculated as 40% of the tyre width (225mm), which means the sidewall height has 90 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 225/65 R17
(2275.46 mm), 315/35 R20
(2288.65 mm), 235/40 R18
(2026.96 mm), 235/50 R19
(2254.41 mm), 235/65 R16
(2236.5 mm), 155/70 R13
(1719.08 mm), 245/35 R19
(2054.92 mm).
