Tire Size Calculator
Width (mm)
Aspect Ratio (%)
Rim (in)
✓Tire Dimensions
Outer Diameter (mm)
634.3
Sidewall (mm)
101.3
Circumference (mm)
1992.7
Tyre notation (e.g. 225/45R17) encodes tread width in mm, sidewall height as % of width, construction type (R = radial), and rim diameter in inches.
- 1Sidewall height (mm) = Width × Aspect ratio / 100
- 2Overall diameter (mm) = Rim (in) × 25.4 + 2 × Sidewall
- 3Circumference = π × Overall diameter
- 4Changing tyre size affects speedometer and odometer accuracy
225/45R17=Sidewall = 101.25mm; Diameter = 634.5mm; Circumference ≈ 1,993mm
| Element | Example | Meaning |
|---|---|---|
| Width | 225 | 225mm tread width |
| Aspect ratio | /45 | Sidewall = 45% of 225mm |
| Construction | R | Radial |
| Rim diameter | 17 | 17-inch rim |
| Load index | 91 | 615 kg max per tyre |
References
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