Home Back

Wheel Size Speed Calculator

Speed Formula:

\[ S = \frac{RPM \times \pi \times WS}{1056} \]

rpm
inches

Unit Converter ▲

Unit Converter ▼

From: To:

1. What is a Wheel Size Speed Calculator?

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.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ S = \frac{RPM \times \pi \times WS}{1056} \]

Where:

Explanation: The formula calculates how much distance the wheel covers in one minute (circumference × RPM) and converts it to miles per hour.

3. Importance of Speed Calculation

Details: Accurate speed calculation is crucial for gear ratio selection, speedometer calibration, and performance tuning.

4. Using the Calculator

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.

5. Frequently Asked Questions (FAQ)

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.

Wheel Size Speed Calculator© - All Rights Reserved 2025