235/40R19 vs 235/45R18
235/45R18 is 2.0 mm shorter than 235/40R19 in overall diameter (−0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 235/45R18 fitted, the speedometer reads 100 km/h when you are doing 99.7 km/h.
Dimensions side by side
| 235/40R19 | 235/45R18 | |
|---|---|---|
| Overall diameter | 671 mm (26.4″) | 669 mm (26.3″) |
| Section width | 235 mm | 235 mm |
| Sidewall height | 94 mm | 106 mm |
| Rim | 19″ | 18″ |
| Revolutions per km | 474 | 476 |
| In stock | 71 tires from $144.00 | 88 tires from $111.00 |
What changes
- Overall diameter: 235/45R18 is 2.0 mm shorter (−0.3%).
- Speedometer: reads 100 km/h at an actual 99.7 km/h with 235/45R18.
- 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 235/40R19
Vehicles that use 235/45R18
See every alternate size for 235/40R19
Frequently asked questions
Can I use 235/45R18 instead of 235/40R19?
Usually, yes: 235/45R18 is within 3% of the overall diameter of 235/40R19 (−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 235/40R19 and 235/45R18?
With 235/45R18 instead of 235/40R19, the speedometer shows 100 km/h when you are actually doing 99.7 km/h.
Which vehicles came with both 235/40R19 and 235/45R18?
Both sizes were original equipment, on different trims or packages, on the 2014–2015, 2019–2024 Volvo S60, 2015–2024 Lexus RC, 2017–2024 Porsche 718, 2017–2024 Tesla Model 3, 2023–2024 Lexus ES, 2023–2024 Lexus IS.