265/40R21 vs 265/45R20
265/45R20 is 2.0 mm taller than 265/40R21 in overall diameter (+0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 265/45R20 fitted, the speedometer reads 100 km/h when you are doing 100.3 km/h.
Dimensions side by side
| 265/40R21 | 265/45R20 | |
|---|---|---|
| Overall diameter | 745 mm (29.3″) | 747 mm (29.4″) |
| Section width | 265 mm | 265 mm |
| Sidewall height | 106 mm | 119 mm |
| Rim | 21″ | 20″ |
| Revolutions per km | 427 | 426 |
| In stock | 33 tires from $295.00 | 38 tires from $162.00 |
What changes
- Overall diameter: 265/45R20 is 2.0 mm taller (+0.3%).
- Speedometer: reads 100 km/h at an actual 100.3 km/h with 265/45R20.
- 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 265/40R21
Vehicles that use 265/45R20
See every alternate size for 265/40R21
Frequently asked questions
Can I use 265/45R20 instead of 265/40R21?
Usually, yes: 265/45R20 is within 3% of the overall diameter of 265/40R21 (+0.3%). 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 265/40R21 and 265/45R20?
With 265/45R20 instead of 265/40R21, the speedometer shows 100 km/h when you are actually doing 100.3 km/h.
Which vehicles came with both 265/40R21 and 265/45R20?
Both sizes were original equipment, on different trims or packages, on the 2015–2024 Porsche Macan, 2020–2024 BMW X3, 2020–2024 BMW X4, 2017–2023 Maserati Levante, 2018–2021 Mercedes-Benz GLC 63, 2018–2021 Mercedes-Benz GLC 63 S.