285/70 R19.5 doesn't belong to the most popular dimensions for winter 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 - 70 is height of the tyre, which is calculated as 70% of the tyre width (285mm), which means the sidewall height has 199.5 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 200/55 R17(2047.69 mm), 265/55 R19(2431.91 mm), 205/50 R17(2000.57 mm), 275/30 R19(2034.5 mm), 205/65 R16(2113.98 mm), 275/40 R19(2207.28 mm), 215/45 R16(1884.64 mm). The same goes for weight indexes: 146.