225/55R17 vs 245/45R18
245/45R18 is 1.0 mm shorter than 225/55R17 in overall diameter (−0.1%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 245/45R18 fitted, the speedometer reads 100 km/h when you are doing 99.9 km/h.
Dimensions side by side
| 225/55R17 | 245/45R18 | |
|---|---|---|
| Overall diameter | 679 mm (26.7″) | 678 mm (26.7″) |
| Section width | 225 mm | 245 mm |
| Sidewall height | 124 mm | 110 mm |
| Rim | 17″ | 18″ |
| Revolutions per km | 469 | 469 |
| In stock | 61 tires from $119.00 | 50 tires from $118.00 |
What changes
- Overall diameter: 245/45R18 is 1.0 mm shorter (−0.1%).
- Speedometer: reads 100 km/h at an actual 99.9 km/h with 245/45R18.
- 245/45R18 is 20 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 225/55R17
Vehicles that use 245/45R18
See every alternate size for 225/55R17
Frequently asked questions
Can I use 245/45R18 instead of 225/55R17?
Usually, yes: 245/45R18 is within 3% of the overall diameter of 225/55R17 (−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 225/55R17 and 245/45R18?
With 245/45R18 instead of 225/55R17, the speedometer shows 100 km/h when you are actually doing 99.9 km/h.
Which vehicles came with both 225/55R17 and 245/45R18?
Both sizes were original equipment, on different trims or packages, on the 2016–2024 Chevrolet Malibu, 2018–2020 Buick Regal Sportback, 2017–2019 Mercedes-Benz E300, 2016 BMW 528i, 2012–2014 Audi A6, 2009–2010 Infiniti G37.