255/40R19 vs 255/45R18
255/45R18 is 0.0 mm taller than 255/40R19 in overall diameter (±0.0%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 255/45R18 fitted, the speedometer reads 100 km/h when you are doing 100.0 km/h.
Dimensions side by side
| 255/40R19 | 255/45R18 | |
|---|---|---|
| Overall diameter | 687 mm (27.0″) | 687 mm (27.0″) |
| Section width | 255 mm | 255 mm |
| Sidewall height | 102 mm | 115 mm |
| Rim | 19″ | 18″ |
| Revolutions per km | 463 | 463 |
| In stock | 35 tires from $154.00 | 5 tires from $181.00 |
What changes
- Overall diameter: 255/45R18 is 0.0 mm taller (±0.0%).
- Speedometer: reads 100 km/h at an actual 100.0 km/h with 255/45R18.
- Wheel size changes from 19″ to 18″: 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 255/40R19
Vehicles that use 255/45R18
See every alternate size for 255/40R19
Frequently asked questions
Can I use 255/45R18 instead of 255/40R19?
Usually, yes: 255/45R18 is within 3% of the overall diameter of 255/40R19 (±0.0%). 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 255/40R19 and 255/45R18?
With 255/45R18 instead of 255/40R19, the speedometer shows 100 km/h when you are actually doing 100.0 km/h.
Which vehicles came with both 255/40R19 and 255/45R18?
Both sizes were original equipment, on different trims or packages, on the 2017–2019 BMW 330i, 2017–2019 BMW 340i, 2014–2016 BMW 328i, 2014–2016 BMW 335i, 2007–2010, 2014 Mercedes-Benz CL550, 2012–2013 Mercedes-Benz S350.