275/35R21 vs 275/40R20
275/40R20 is 2.0 mm taller than 275/35R21 in overall diameter (+0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/40R20 fitted, the speedometer reads 100 km/h when you are doing 100.3 km/h.
Dimensions side by side
| 275/35R21 | 275/40R20 | |
|---|---|---|
| Overall diameter | 726 mm (28.6″) | 728 mm (28.7″) |
| Section width | 275 mm | 275 mm |
| Sidewall height | 96 mm | 110 mm |
| Rim | 21″ | 20″ |
| Revolutions per km | 438 | 437 |
| In stock | 23 tires from $160.00 | 39 tires from $143.00 |
What changes
- Overall diameter: 275/40R20 is 2.0 mm taller (+0.3%).
- Speedometer: reads 100 km/h at an actual 100.3 km/h with 275/40R20.
- 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 275/35R21
Vehicles that use 275/40R20
See every alternate size for 275/35R21
Frequently asked questions
Can I use 275/40R20 instead of 275/35R21?
Usually, yes: 275/40R20 is within 3% of the overall diameter of 275/35R21 (+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 275/35R21 and 275/40R20?
With 275/40R20 instead of 275/35R21, the speedometer shows 100 km/h when you are actually doing 100.3 km/h.
Which vehicles came with both 275/35R21 and 275/40R20?
Both sizes were original equipment, on different trims or packages, on the 2017–2024 Porsche Panamera, 2018–2024 BMW X3, 2018–2024 Lexus LC, 2019–2024 BMW X4, 2018–2023 Porsche Panamera Sport Turismo, 2014–2019 Bentley Flying Spur.