235/40R18 vs 235/45R17
235/45R17 is 2.0 mm shorter than 235/40R18 in overall diameter (−0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 235/45R17 fitted, the speedometer reads 100 km/h when you are doing 99.7 km/h.
Dimensions side by side
| 235/40R18 | 235/45R17 | |
|---|---|---|
| Overall diameter | 645 mm (25.4″) | 643 mm (25.3″) |
| Section width | 235 mm | 235 mm |
| Sidewall height | 94 mm | 106 mm |
| Rim | 18″ | 17″ |
| Revolutions per km | 494 | 495 |
| In stock | 45 tires from $110.00 | 21 tires from $119.00 |
What changes
- Overall diameter: 235/45R17 is 2.0 mm shorter (−0.3%).
- Speedometer: reads 100 km/h at an actual 99.7 km/h with 235/45R17.
- Wheel size changes from 18″ to 17″: 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 235/40R18
Vehicles that use 235/45R17
See every alternate size for 235/40R18
Frequently asked questions
Can I use 235/45R17 instead of 235/40R18?
Usually, yes: 235/45R17 is within 3% of the overall diameter of 235/40R18 (−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 235/40R18 and 235/45R17?
With 235/45R17 instead of 235/40R18, the speedometer shows 100 km/h when you are actually doing 99.7 km/h.
Which vehicles came with both 235/40R18 and 235/45R17?
Both sizes were original equipment, on different trims or packages, on the 2004–2009, 2011–2017 Volvo S60, 2009–2017 Volkswagen CC, 2015–2017 Volvo V60, 2007–2015 Volkswagen Eos, 2006–2013 Volvo C70, 2010–2013 Mercedes-Benz E350.