275/30 R21 - Best winter tyres 2025 - market overview, tests, reviews

275/30 R21 doesn't belong to the most popular dimensions for winter tyres - there are 2 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 (275mm), which means the sidewall height has 82.5 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 2194.09 mm, which is very similar to 225/65 R16(2195.66 mm), 195/75 R16(2195.66 mm), 155/70 R19(2197.86 mm), 275/35 R20(2200.69 mm), 225/70 R15(2186.55 mm), 265/45 R18(2185.61 mm), 245/55 R17(2203.2 mm). There are multiple speed indexes available for winter tyres in 275/30 R21: W(270km/h). The same goes for weight indexes: 98.