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

325/30 R21 doesn't belong to the most popular dimensions for tyres - there are tyre models available, which can be compared to 325/25 R20, 155/60 R15, 155/65 R13. 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 mm, which is very similar to 225/65 R17(2275.46 mm), 315/35 R20(2288.65 mm), 235/40 R18(2026.96 mm), 235/50 R19(2254.41 mm), 235/65 R16(2236.5 mm), 155/70 R13(1719.08 mm), 245/35 R19(2054.92 mm).