205/55R16 vs 225/40R18
225/40R18 is 5.0 mm taller than 205/55R16 in overall diameter (+0.8%), 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 100.8 km/h.
Dimensions side by side
| 205/55R16 | 225/40R18 | |
|---|---|---|
| Overall diameter | 632 mm (24.9″) | 637 mm (25.1″) |
| Section width | 205 mm | 225 mm |
| Sidewall height | 113 mm | 90 mm |
| Rim | 16″ | 18″ |
| Revolutions per km | 504 | 500 |
| In stock | 92 tires from $88.00 | 77 tires from $110.00 |
What changes
- Overall diameter: 225/40R18 is 5.0 mm taller (+0.8%).
- Speedometer: reads 100 km/h at an actual 100.8 km/h with 225/40R18.
- 225/40R18 is 20 mm wider, so check clearance and the recommended rim width.
- Wheel size changes from 16″ 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 205/55R16
Vehicles that use 225/40R18
See every alternate size for 205/55R16
Frequently asked questions
Can I use 225/40R18 instead of 205/55R16?
Usually, yes: 225/40R18 is within 3% of the overall diameter of 205/55R16 (+0.8%). 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 205/55R16 and 225/40R18?
With 225/40R18 instead of 205/55R16, the speedometer shows 100 km/h when you are actually doing 100.8 km/h.
Which vehicles came with both 205/55R16 and 225/40R18?
Both sizes were original equipment, on different trims or packages, on the 2016–2021 Mini Clubman, 2016–2021 Mini Cooper, 2017–2018 Volkswagen Golf, 2010, 2012–2016 Volkswagen Jetta, 2014–2016 Audi A3, 2003, 2007–2008 Jaguar X-Type.