1. What is an RPM And Speed Calculator?

Definition: This calculator estimates the speed based on rotational speed (RPM), diameter, and a constant.

Purpose: It helps automotive professionals, engineers, and mechanics determine vehicle speed based on wheel/tire rotations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Revolutions per minute
• \( D \) — Diameter (inches)
• \( C \) — Conversion constant (typically 336)

Explanation: The RPM is multiplied by the constant (which incorporates unit conversions) and divided by diameter to get speed in mph.

3. Importance of RPM to Speed Calculation

Details: This calculation is essential for gear ratio selection, speedometer calibration, and performance tuning.

4. Using the Calculator

Tips: Enter the RPM, diameter in inches, and constant (default 336). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Where does the constant 336 come from?
A: It combines unit conversions (inches to miles and minutes to hours) with π (pi) for circumference calculation.

Q2: What diameter should I use?
A: Use the overall diameter of your wheel/tire combination, including any deflection under load.

Q3: How accurate is this calculation?
A: It provides theoretical speed. Actual speed may vary due to tire slip, wear, and other factors.

Q4: Can I use this for different units?
A: The constant changes for different units. For km/h, use ~213 instead of 336.

Q5: Does this work for any rotating object?
A: Yes, you can calculate linear speed for any rotating object if you know its RPM and diameter.