225/40R18 in inches
A 225/40R18 tire stands 25.1 inches tall and is 8.9 inches wide. It fits an 18-inch wheel.
Tall
25.1″
637 mm
Wide
8.9″
225 mm
Wheel
18″
rim diameter
Cars that come with 225/40R18
Similar-height sizes
Within 3% of 225/40R18, so your speedometer stays close.
| Size | Height | vs 225/40R18 | |
|---|---|---|---|
| 195/65R15 | 25.0″ | −0.4%needs 15″ wheels | Compare |
| 225/45R17 | 25.0″ | −0.5%needs 17″ wheels | Compare |
| 265/30R19 | 25.3″ | +0.7%needs 19″ wheels | Compare |
| 205/55R16 | 24.9″ | −0.8%needs 16″ wheels | Compare |
| 215/55R16 | 25.3″ | +0.9%needs 16″ wheels | Compare |
| 235/40R18 | 25.4″ | +1.3% | Compare |
| 215/50R17 | 25.5″ | +1.5%needs 17″ wheels | Compare |
| 215/45R17 | 24.6″ | −1.9%needs 17″ wheels | Compare |
How 225/40R18 is measured
| Measurement | Inches | Millimetres |
|---|---|---|
| Overall height (diameter) | 25.09 | 637 |
| Tread width | 8.86 | 225 |
| Sidewall height | 3.54 | 90 |
| Distance per turn (circumference) | 78.8 | 2002 |
| Turns per mile | 804 | |
The first number (225) is the width in millimetres. The second (40) means the sidewall is 40% as tall as the tire is wide. The last (18) is the wheel size in inches. More on reading a tire size.