275/50 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 - 50 is height of the tyre, which is calculated as 50% of the tyre width (275mm), which means the sidewall height has 137.5 mm. The wheel diameter is R20, which means it fits to a 20 inch/508mm diameter wheel. The total circumference of the tyre is 2459.87 mm, which is very similar to 275/55 R19(2466.46 mm), 275/45 R21(2453.27 mm), 315/40 R21(2467.41 mm), 285/40 R22(2471.81 mm), 275/40 R22(2446.67 mm), 255/55 R20(2477.15 mm), 265/70 R16(2442.27 mm). There are multiple speed indexes available for allround tyres in 275/50 R20: H(210km/h), W(270km/h). The same goes for weight indexes: 109, 113.