255/40R20 Tire Size Specifications & Compatible Vehicles
Overall Diameter
712.0 mm
Section Width
255 mm
Sidewall Height
102.0 mm
Circumference
2236.8 mm
Revs/Mile
719
Rim Diameter
20"
Inch Equivalent
28x10R20
Rim Width (ETRTO)
7.5" – 10.0"
Compatible Vehicles
The following vehicles use 255/40R20 tires from the factory:
2025 Audi A6 Prestige 55 TFSI quattro 2024 Audi A6 Prestige 55 TFSI quattro 2023 Audi A6 Prestige 55 TFSI quattro 2022 Audi A6 Prestige 55 TFSI quattro 2025 Volvo XC60 Ultimate B6 AWD 2024 Volvo XC60 Ultimate B6 AWD 2023 Volvo XC60 B6 Inscription 2022 Volvo XC60 T6 R-Design 2021 Volvo XC60 T6 R-Design 2020 Volvo XC60 T6 R-Design
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 255/40R20 and may be used as replacements:
Popular Comparisons
See how 255/40R20 compares to other common tire sizes:
Understanding 255/40R20
The tire size 255/40R20 means the tire has a section width of 255mm, an aspect ratio of 40% (the sidewall height is 40% of the width), and fits a 20-inch rim.
Sidewall Height = 255 x 0.4 = 102.0 mm
Overall Diameter = (102.0 x 2) + (20 x 25.4) = 712.0 mm
Circumference = 712.0 x π = 2236.8 mm
Overall Diameter = (102.0 x 2) + (20 x 25.4) = 712.0 mm
Circumference = 712.0 x π = 2236.8 mm
Frequently Asked Questions
The 255/40R20 tire size is used on 10 vehicle trims including the 2025 Audi A6, 2024 Audi A6, 2023 Audi A6 and 7 more.
A 255/40R20 tire has an overall diameter of 712.0mm (28.0 inches). The sidewall height is 102.0mm, and the total circumference is 2237mm.
For 255/40R20 tires, the ETRTO recommended rim width is 8.5". The acceptable range is 7.5" minimum to 10.0" maximum. Using a rim outside this range can cause improper bead seating and unsafe handling.
Yes, as long as the replacement tire overall diameter is within 3% of the 255/40R20 712.0mm diameter. Compatible alternatives include 255/45R19, 255/35R21, 255/50R18. Use our Tire Size Calculator to compare any two sizes.