Tire Size Converter
Calculate tire dimensions, circumference, and compare speedometer differences between tire sizes
Tire Size: 225/45R17
Tire Dimensions
Overall Diameter
24.97"
634.3 mm
Sidewall Height
3.99"
101.25 mm
Circumference
78.45"
1,992.71 mm
Section Width
8.86"
225 mm
Revs per Mile
807.61
Revs per km
501.83
Size Comparison
Speedometer difference if switching from your tire size:
| Tire Size | Diameter | Speed Diff | At 60 MPH shows |
|---|---|---|---|
| 205/55R16 | 24.88" | -0.38% | 59.77 MPH actual |
| 215/50R17 | 25.46" | +1.97% | 61.18 MPH actual |
| 225/45R17 | 24.97" | 0% | 60 MPH actual |
| 235/40R18 | 25.4" | +1.72% | 61.03 MPH actual |
| 245/35R19 | 25.75" | +3.12% | 61.87 MPH actual |
Common Tire Sizes
Reading Tire Sizes
A tire marked 225/45R17 means:
- 225: Section width in millimeters
- 45: Aspect ratio (sidewall height is 45% of width)
- R: Radial construction
- 17: Rim diameter in inches
Tip: When changing tire sizes, try to stay within 3% of the original overall diameter to maintain accurate speedometer readings.