255/40R18 vs 285/30R19
285/30R19 is 7.0 mm shorter than 255/40R18 in overall diameter (−1.1%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 285/30R19 fitted, the speedometer reads 100 km/h when you are doing 98.9 km/h.
Dimensions side by side
| 255/40R18 | 285/30R19 | |
|---|---|---|
| Overall diameter | 661 mm (26.0″) | 654 mm (25.7″) |
| Section width | 255 mm | 285 mm |
| Sidewall height | 102 mm | 86 mm |
| Rim | 18″ | 19″ |
| Revolutions per km | 482 | 487 |
| In stock | 13 tires from $238.00 | 10 tires from $285.00 |
What changes
- Overall diameter: 285/30R19 is 7.0 mm shorter (−1.1%).
- Speedometer: reads 100 km/h at an actual 98.9 km/h with 285/30R19.
- 285/30R19 is 30 mm wider, so check clearance and the recommended rim width.
- Wheel size changes from 18″ to 19″: 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 255/40R18
Vehicles that use 285/30R19
See every alternate size for 255/40R18
Frequently asked questions
Can I use 285/30R19 instead of 255/40R18?
Usually, yes: 285/30R19 is within 3% of the overall diameter of 255/40R18 (−1.1%). 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 255/40R18 and 285/30R19?
With 285/30R19 instead of 255/40R18, the speedometer shows 100 km/h when you are actually doing 98.9 km/h.
Which vehicles came with both 255/40R18 and 285/30R19?
Both sizes were original equipment, on different trims or packages, on the 2017–2021 Mercedes-Benz C63, 2010–2018 Mercedes-Benz CLS550, 2010–2018 Mercedes-Benz SL550, 2016–2017 Mercedes-Benz CLS400, 2017 Mercedes-Benz SL450, 2016 Mercedes-Benz SL400.