315/30 R21 - Best allround tyres 2025 - market overview, tests, reviews

315/30 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, 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 (315mm), which means the sidewall height has 94.5 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 2269.49 mm, which is very similar to 195/55 R20(2269.8 mm), 225/70 R16(2266.34 mm), 225/65 R17(2275.46 mm), 265/40 R20(2261.95 mm), 215/80 R15(2277.65 mm), 235/45 R20(2260.38 mm), 275/35 R21(2280.48 mm).