275/40R19 vs 275/45R18
275/45R18 is 2.0 mm taller than 275/40R19 in overall diameter (+0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/45R18 fitted, the speedometer reads 100 km/h when you are doing 100.3 km/h.
Dimensions side by side
| 275/40R19 | 275/45R18 | |
|---|---|---|
| Overall diameter | 703 mm (27.7″) | 705 mm (27.8″) |
| Section width | 275 mm | 275 mm |
| Sidewall height | 110 mm | 124 mm |
| Rim | 19″ | 18″ |
| Revolutions per km | 453 | 452 |
| In stock | 24 tires from $158.00 | 1 tire from $271.00 |
What changes
- Overall diameter: 275/45R18 is 2.0 mm taller (+0.3%).
- Speedometer: reads 100 km/h at an actual 100.3 km/h with 275/45R18.
- 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 275/40R19
Vehicles that use 275/45R18
See every alternate size for 275/40R19
Frequently asked questions
Can I use 275/45R18 instead of 275/40R19?
Usually, yes: 275/45R18 is within 3% of the overall diameter of 275/40R19 (+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 275/40R19 and 275/45R18?
With 275/45R18 instead of 275/40R19, the speedometer shows 100 km/h when you are actually doing 100.3 km/h.
Which vehicles came with both 275/40R19 and 275/45R18?
Both sizes were original equipment, on different trims or packages, on the 2014 Maserati Ghibli, 2009–2010 Mercedes-Benz CL600, 2007–2009 Mercedes-Benz CL550.