255/55R20 vs 275/45R21
275/45R21 is 8.0 mm shorter than 255/55R20 in overall diameter (−1.0%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/45R21 fitted, the speedometer reads 100 km/h when you are doing 99.0 km/h.
Dimensions side by side
| 255/55R20 | 275/45R21 | |
|---|---|---|
| Overall diameter | 789 mm (31.1″) | 781 mm (30.7″) |
| Section width | 255 mm | 275 mm |
| Sidewall height | 140 mm | 124 mm |
| Rim | 20″ | 21″ |
| Revolutions per km | 403 | 408 |
| In stock | 37 tires from $175.00 | 30 tires from $216.00 |
What changes
- Overall diameter: 275/45R21 is 8.0 mm shorter (−1.0%).
- Speedometer: reads 100 km/h at an actual 99.0 km/h with 275/45R21.
- 275/45R21 is 20 mm wider, so check clearance and the recommended rim width.
- Wheel size changes from 20″ to 21″: you need wheels in the new size.
- Choose a load index at least as high as the one on your door placard.
Vehicles that came with both sizes
Vehicles that use 255/55R20
Vehicles that use 275/45R21
See every alternate size for 255/55R20
Frequently asked questions
Can I use 275/45R21 instead of 255/55R20?
Usually, yes: 275/45R21 is within 3% of the overall diameter of 255/55R20 (−1.0%). Use wheels of the right size and width, match or exceed the original load index, and check clearance at full steering lock.
How much does the speedometer change between 255/55R20 and 275/45R21?
With 275/45R21 instead of 255/55R20, the speedometer shows 100 km/h when you are actually doing 99.0 km/h.
Which vehicles came with both 255/55R20 and 275/45R21?
Both sizes were original equipment, on different trims or packages, on the 2017–2024 Land Rover Discovery, 2020–2024 Ford Explorer, 2014–2022 Land Rover Range Rover Sport, 2014–2015, 2019–2022 Land Rover Range Rover, 2020 Lincoln Aviator.