245/45R20 vs 275/35R21
275/35R21 is 3.0 mm shorter than 245/45R20 in overall diameter (−0.4%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/35R21 fitted, the speedometer reads 100 km/h when you are doing 99.6 km/h.
Dimensions side by side
| 245/45R20 | 275/35R21 | |
|---|---|---|
| Overall diameter | 729 mm (28.7″) | 726 mm (28.6″) |
| Section width | 245 mm | 275 mm |
| Sidewall height | 110 mm | 96 mm |
| Rim | 20″ | 21″ |
| Revolutions per km | 437 | 438 |
| In stock | 52 tires from $167.00 | 23 tires from $160.00 |
What changes
- Overall diameter: 275/35R21 is 3.0 mm shorter (−0.4%).
- Speedometer: reads 100 km/h at an actual 99.6 km/h with 275/35R21.
- 275/35R21 is 30 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 245/45R20
Vehicles that use 275/35R21
See every alternate size for 245/45R20
Frequently asked questions
Can I use 275/35R21 instead of 245/45R20?
Usually, yes: 275/35R21 is within 3% of the overall diameter of 245/45R20 (−0.4%). 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 245/45R20 and 275/35R21?
With 275/35R21 instead of 245/45R20, the speedometer shows 100 km/h when you are actually doing 99.6 km/h.
Which vehicles came with both 245/45R20 and 275/35R21?
Both sizes were original equipment, on different trims or packages, on the 2018–2024 BMW X3, 2018–2024 Lexus LC, 2019–2024 BMW X4, 2010–2015 Chevrolet Camaro.