265/40 R21 - Best tyres 2025 - market overview, tests, reviews

265/40 R21 doesn't belong to the most popular dimensions for tyres - there are tyre models available, which can be compared to 325/30 R21, 155/60 R15, 155/65 R13. Let's break down the sizing - 40 is height of the tyre, which is calculated as 40% of the tyre width (265mm), which means the sidewall height has 106 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 235/65 R18(2396.09 mm), 155/80 R13(1816.47 mm), 245/35 R21(2214.51 mm), 165/65 R13(1711.23 mm), 245/45 R19(2208.85 mm), 175/55 R15(1801.7 mm), 245/70 R16(2354.31 mm).