275/45 R21 - Best tyres 2025 - market overview, tests, reviews

275/45 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 - 45 is height of the tyre, which is calculated as 45% of the tyre width (275mm), which means the sidewall height has 123.75 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 285/35 R21(2302.47 mm), 225/35 R19(2010.93 mm), 285/50 R20(2491.28 mm), 225/50 R17(2063.4 mm), 295/35 R19(2164.87 mm), 225/60 R17(2204.77 mm), 305/30 R20(2170.84 mm).