265/30 R21 doesn't belong to the most popular dimensions for winter tyres - there are 1 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 (265mm), which means the sidewall height has 79.5 mm. The wheel diameter is R21, which means it fits to a 21 inch/533.4mm diameter wheel. The total circumference of the tyre is 2175.24 mm, which is very similar to 235/50 R18
(2174.61 mm), 195/80 R15
(2177.12 mm), 265/35 R20
(2178.69 mm), 215/55 R18
(2179.32 mm), 305/30 R20
(2170.84 mm), 235/45 R19
(2180.58 mm), 235/55 R17
(2168.64 mm). There are multiple speed indexes available for winter tyres in 265/30 R21: W
(270km/h). The same goes for weight indexes: 96.
