245/40R21 vs 245/45R20
245/45R20 is 0.0 mm taller than 245/40R21 in overall diameter (±0.0%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 245/45R20 fitted, the speedometer reads 100 km/h when you are doing 100.0 km/h.
Dimensions side by side
| 245/40R21 | 245/45R20 | |
|---|---|---|
| Overall diameter | 729 mm (28.7″) | 729 mm (28.7″) |
| Section width | 245 mm | 245 mm |
| Sidewall height | 98 mm | 110 mm |
| Rim | 21″ | 20″ |
| Revolutions per km | 437 | 437 |
| In stock | 10 tires from $398.00 | 52 tires from $167.00 |
What changes
- Overall diameter: 245/45R20 is 0.0 mm taller (±0.0%).
- Speedometer: reads 100 km/h at an actual 100.0 km/h with 245/45R20.
- Wheel size changes from 21″ to 20″: 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 245/40R21
Vehicles that use 245/45R20
See every alternate size for 245/40R21
Frequently asked questions
Can I use 245/45R20 instead of 245/40R21?
Usually, yes: 245/45R20 is within 3% of the overall diameter of 245/40R21 (±0.0%). 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 245/40R21 and 245/45R20?
With 245/45R20 instead of 245/40R21, the speedometer shows 100 km/h when you are actually doing 100.0 km/h.
Which vehicles came with both 245/40R21 and 245/45R20?
Both sizes were original equipment, on different trims or packages, on the 2019–2022, 2024 Volvo XC40, 2018–2024 BMW X3, 2018–2024 Lexus LC, 2018–2024 Volvo V90 Cross Country, 2019–2024 BMW X4, 2010–2015 Chevrolet Camaro.