285/35R23 vs 285/45R21
285/45R21 is 6.0 mm taller than 285/35R23 in overall diameter (+0.8%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 285/45R21 fitted, the speedometer reads 100 km/h when you are doing 100.8 km/h.
Dimensions side by side
| 285/35R23 | 285/45R21 | |
|---|---|---|
| Overall diameter | 784 mm (30.9″) | 790 mm (31.1″) |
| Section width | 285 mm | 285 mm |
| Sidewall height | 100 mm | 128 mm |
| Rim | 23″ | 21″ |
| Revolutions per km | 406 | 403 |
| In stock | 3 tires from $563.00 | 23 tires from $400.00 |
What changes
- Overall diameter: 285/45R21 is 6.0 mm taller (+0.8%).
- Speedometer: reads 100 km/h at an actual 100.8 km/h with 285/45R21.
- Wheel size changes from 23″ 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 285/35R23
Vehicles that use 285/45R21
See every alternate size for 285/35R23
Frequently asked questions
Can I use 285/45R21 instead of 285/35R23?
Usually, yes: 285/45R21 is within 3% of the overall diameter of 285/35R23 (+0.8%). 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 285/35R23 and 285/45R21?
With 285/45R21 instead of 285/35R23, the speedometer shows 100 km/h when you are actually doing 100.8 km/h.
Which vehicles came with both 285/35R23 and 285/45R21?
Both sizes were original equipment, on different trims or packages, on the 2021–2024 BMW Alpina XB7, 2024 Audi SQ8, 2019–2023 Lamborghini Urus.