275/40R20 tire size breakdown:
275 = Tire width is 275 mm
40 = Aspect ratio (sidewall height is 40% of 275 mm)
Sidewall height = 110 mm
R = Radial construction
20 = Fits a 20-inch wheel (rim)
Dimensions
Sidewall height: 110 mm (4.33 inches)
Rim diameter: 20 inches
Overall tire diameter: ≈ 30.7 inches (780 mm)
Circumference: ≈ 96.4 inches (2.45 m)
Commonly Found On
This size is often used on performance SUVs and luxury vehicles such as:
BMW X5
BMW X6
Porsche Cayenne
Range Rover Sport
Audi Q7
It provides a balance of sporty handling, stability, and comfort.