225/50R17 vs 235/45R18
235/45R18 is 12.0 mm taller than 225/50R17 in overall diameter (+1.8%), 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 101.8 km/h.
Dimensions side by side
| 225/50R17 | 235/45R18 | |
|---|---|---|
| Overall diameter | 657 mm (25.9″) | 669 mm (26.3″) |
| Section width | 225 mm | 235 mm |
| Sidewall height | 113 mm | 106 mm |
| Rim | 17″ | 18″ |
| Revolutions per km | 484 | 476 |
| In stock | 51 tires from $111.00 | 88 tires from $111.00 |
What changes
- Overall diameter: 235/45R18 is 12.0 mm taller (+1.8%).
- Speedometer: reads 100 km/h at an actual 101.8 km/h with 235/45R18.
- 235/45R18 is 10 mm wider, so check clearance and the recommended rim width.
- Wheel size changes from 17″ 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 225/50R17
Vehicles that use 235/45R18
See every alternate size for 225/50R17
Frequently asked questions
Can I use 235/45R18 instead of 225/50R17?
Usually, yes: 235/45R18 is within 3% of the overall diameter of 225/50R17 (+1.8%). 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 225/50R17 and 235/45R18?
With 235/45R18 instead of 225/50R17, the speedometer shows 100 km/h when you are actually doing 101.8 km/h.
Which vehicles came with both 225/50R17 and 235/45R18?
Both sizes were original equipment, on different trims or packages, on the 2014–2019 Ford Fusion, 2019 Volvo V60, 2013–2015 Lexus GS, 2012–2013 Buick Verano, 2009–2011 Saab 45538, 2006–2008 Mitsubishi Eclipse.