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Tire Height Formula:
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Tire height is the overall diameter of a tire when mounted and inflated, measured from the bottom of the tire to the top through the exact center. It's a crucial measurement for vehicle fitment and performance.
The calculator uses the tire height formula:
Where:
Explanation: The formula converts the sidewall measurement from mm to inches (twice, for both top and bottom sidewalls) and adds the rim diameter to get total tire height.
Details: Proper tire height is essential for maintaining accurate speedometer readings, ensuring proper clearance in wheel wells, and maintaining vehicle handling characteristics. Significant changes can affect gearing and ABS systems.
Tips: Enter sidewall height in millimeters and rim diameter in inches. Both values must be positive numbers. The sidewall height is often found as the second number in the tire size (e.g., in 225/45R17, 45 is the aspect ratio which is a percentage of the tire width).
Q1: How do I find my sidewall height?
A: For a tire marked 225/45R17, the sidewall height is 45% of 225mm (101.25mm). The calculator needs the actual sidewall height in mm.
Q2: Why is tire height important?
A: It affects speedometer accuracy, gear ratios, clearance, and overall vehicle dynamics. Larger tires can improve ground clearance but may reduce acceleration.
Q3: What's the maximum tire height change recommended?
A: Generally, staying within ±3% of original height maintains proper vehicle function, but check your vehicle's specifications.
Q4: Does tire height affect fuel economy?
A: Yes, taller tires typically reduce engine RPM at highway speeds but may decrease acceleration, potentially affecting fuel economy.
Q5: How does tire width relate to height?
A: Width doesn't directly affect height calculation, but aspect ratio (sidewall height) is a percentage of the tire's width.