255/45R18 vs 275/40R19
275/40R19 is 16.0 mm taller than 255/45R18 in overall diameter (+2.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/40R19 fitted, the speedometer reads 100 km/h when you are doing 102.3 km/h.
Dimensions side by side
| 255/45R18 | 275/40R19 | |
|---|---|---|
| Overall diameter | 687 mm (27.0″) | 703 mm (27.7″) |
| Section width | 255 mm | 275 mm |
| Sidewall height | 115 mm | 110 mm |
| Rim | 18″ | 19″ |
| Revolutions per km | 463 | 453 |
| In stock | 5 tires from $181.00 | 24 tires from $158.00 |
What changes
- Overall diameter: 275/40R19 is 16.0 mm taller (+2.3%).
- Speedometer: reads 100 km/h at an actual 102.3 km/h with 275/40R19.
- 275/40R19 is 20 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 255/45R18
Vehicles that use 275/40R19
See every alternate size for 255/45R18
Frequently asked questions
Can I use 275/40R19 instead of 255/45R18?
Usually, yes: 275/40R19 is within 3% of the overall diameter of 255/45R18 (+2.3%). 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 255/45R18 and 275/40R19?
With 275/40R19 instead of 255/45R18, the speedometer shows 100 km/h when you are actually doing 102.3 km/h.
Which vehicles came with both 255/45R18 and 275/40R19?
Both sizes were original equipment, on different trims or packages, on the 2012–2013 Mercedes-Benz S350, 2009–2010 Mercedes-Benz CL600, 2006–2009 Cadillac STS, 2006–2009 Cadillac STS-V, 2007–2009 Mercedes-Benz CL550.