325/30 R21 - Best allround tyres 2025 - market overview, tests, reviews

325/30 R21 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, 325/25 R20, 170/60 R17. Let's break down the sizing - 30 is height of the tyre, which is calculated as 30% of the tyre width (325mm), which means the sidewall height has 97.5 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 2288.34 mm, which is very similar to 245/45 R20(2288.65 mm), 315/35 R20(2288.65 mm), 275/40 R20(2287.08 mm), 215/75 R16(2289.91 mm), 245/50 R19(2285.82 mm), 245/40 R21(2291.48 mm), 225/60 R18(2284.57 mm).