215/45R17 vs 225/40R18
225/40R18 is 12.0 mm taller than 215/45R17 in overall diameter (+1.9%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 225/40R18 fitted, the speedometer reads 100 km/h when you are doing 101.9 km/h.
Dimensions side by side
| 215/45R17 | 225/40R18 | |
|---|---|---|
| Overall diameter | 625 mm (24.6″) | 637 mm (25.1″) |
| Section width | 215 mm | 225 mm |
| Sidewall height | 97 mm | 90 mm |
| Rim | 17″ | 18″ |
| Revolutions per km | 509 | 500 |
| In stock | 55 tires from $104.00 | 77 tires from $110.00 |
What changes
- Overall diameter: 225/40R18 is 12.0 mm taller (+1.9%).
- Speedometer: reads 100 km/h at an actual 101.9 km/h with 225/40R18.
- 225/40R18 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 215/45R17
Vehicles that use 225/40R18
See every alternate size for 215/45R17
Frequently asked questions
Can I use 225/40R18 instead of 215/45R17?
Usually, yes: 225/40R18 is within 3% of the overall diameter of 215/45R17 (+1.9%). 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 215/45R17 and 225/40R18?
With 225/40R18 instead of 215/45R17, the speedometer shows 100 km/h when you are actually doing 101.9 km/h.
Which vehicles came with both 215/45R17 and 225/40R18?
Both sizes were original equipment, on different trims or packages, on the 2016–2017, 2020–2021 Hyundai Veloster, 2016–2017 Acura ILX, 2005–2010 Scion tC, 2004–2005 Lexus IS.