265/40R19 vs 265/45R18
265/45R18 is 1.0 mm taller than 265/40R19 in overall diameter (+0.1%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 265/45R18 fitted, the speedometer reads 100 km/h when you are doing 100.1 km/h.
Dimensions side by side
| 265/40R19 | 265/45R18 | |
|---|---|---|
| Overall diameter | 695 mm (27.4″) | 696 mm (27.4″) |
| Section width | 265 mm | 265 mm |
| Sidewall height | 106 mm | 119 mm |
| Rim | 19″ | 18″ |
| Revolutions per km | 458 | 457 |
| In stock | 6 tires from $258.00 | 2 tires from $377.00 |
What changes
- Overall diameter: 265/45R18 is 1.0 mm taller (+0.1%).
- Speedometer: reads 100 km/h at an actual 100.1 km/h with 265/45R18.
- 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 265/40R19
Vehicles that use 265/45R18
See every alternate size for 265/40R19
Frequently asked questions
Can I use 265/45R18 instead of 265/40R19?
Usually, yes: 265/45R18 is within 3% of the overall diameter of 265/40R19 (+0.1%). 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 265/40R19 and 265/45R18?
With 265/45R18 instead of 265/40R19, the speedometer shows 100 km/h when you are actually doing 100.1 km/h.
Which vehicles came with both 265/40R19 and 265/45R18?
Both sizes were original equipment, on different trims or packages, on the 2017–2024 Porsche 718, 2013–2016 Porsche Boxster, 2014–2016 Porsche Cayman, 2011–2014 Cadillac CTS.