1. What is a Vehicle Speed To Wheel RPM Calculator?

Definition: This calculator converts vehicle speed in miles per hour (mph) to wheel revolutions per minute (RPM) based on tire diameter.

Purpose: It helps automotive professionals, engineers, and enthusiasts understand the relationship between vehicle speed and wheel rotation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( WRPM \) — Wheel revolutions per minute
• \( S \) — Vehicle speed (miles per hour)
• \( TD \) — Tire diameter (inches)
• \( 1056 \) — Conversion factor (combining various unit conversions)
• \( \pi \) — Pi (approximately 3.1416)

Explanation: The formula converts speed in mph to inches per minute, then divides by the tire circumference to get revolutions per minute.

3. Importance of Wheel RPM Calculation

Details: Understanding wheel RPM is crucial for gear ratio calculations, performance tuning, speedometer calibration, and transmission design.

4. Using the Calculator

Tips: Enter the vehicle speed in mph and the tire diameter in inches. Both values must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the 1056 constant in the formula?
A: It combines conversions from miles to inches (63,360) and hours to minutes (60) into a single factor (63,360/60 = 1056).

Q2: How do I measure tire diameter accurately?
A: Measure from the ground to the top of the tire (loaded radius) and multiply by 2, or use manufacturer specifications.

Q3: Does this account for tire wear or pressure changes?
A: No, for precise calculations, use actual measured diameter which changes with wear and pressure.

Q4: Can I use this for metric units?
A: The current formula uses imperial units. For metric (km/h and mm), a different conversion factor would be needed.

Q5: How does wheel RPM relate to engine RPM?
A: Engine RPM = Wheel RPM × Final Drive Ratio × Transmission Gear Ratio (accounting for any torque converter slip in automatics).