305/25 R21 - Best winter tyres 2025 - market overview, tests, reviews

305/25 R21 doesn't belong to the most popular dimensions for winter 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 - 25 is height of the tyre, which is calculated as 25% of the tyre width (305mm), which means the sidewall height has 76.25 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 2154.82 mm, which is very similar to 215/65 R16(2154.82 mm), 255/35 R20(2156.7 mm), 255/40 R19(2157.02 mm), 225/45 R19(2152.31 mm), 255/45 R18(2157.33 mm), 295/30 R20(2151.99 mm), 185/75 R16(2148.54 mm).