Speed Formula:
From: | To: |
Definition: This calculator estimates the speed of a vehicle based on its wheel revolutions per minute (RPM) and wheel size.
Purpose: It helps automotive enthusiasts, engineers, and mechanics determine vehicle speed when only RPM and wheel dimensions are known.
The calculator uses the formula:
Where:
Explanation: The formula calculates how much distance the wheel covers in one minute (circumference × RPM) and converts it to miles per hour.
Details: Accurate speed calculation is crucial for gear ratio selection, speedometer calibration, and performance tuning.
Tips: Enter the RPM value and wheel diameter in inches. For accurate results, measure the actual loaded wheel diameter rather than using the tire size designation.
Q1: Why is the conversion factor 1056?
A: It combines 12 (inches to feet) × 5280 (feet to miles) divided by 60 (minutes to hours) = 1056.
Q2: Does this work for any wheeled vehicle?
A: Yes, the calculation works for bicycles, cars, trucks, etc., as long as you have accurate RPM and wheel size.
Q3: How do I measure wheel size accurately?
A: Measure from the ground to the center of the wheel and multiply by 2, or measure the full diameter with the weight of the vehicle on the wheels.
Q4: What if my speedometer is off?
A: This calculator can help diagnose speedometer errors by comparing calculated speed with indicated speed.
Q5: Does this account for tire slip or deformation?
A: No, for precise calculations, consider actual rolling circumference which may differ from theoretical due to factors like tire pressure and load.