1. What is a Wheel Speed Calculator?

Definition: This calculator estimates vehicle speed based on engine RPM and tire diameter.

Purpose: It helps automotive enthusiasts, mechanics, and engineers determine vehicle speed at specific RPMs for different tire sizes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Engine revolutions per minute
• \( \pi \) — Pi (approximately 3.1416)
• \( TD \) — Tire diameter (inches)
• 1056 — Conversion factor (combines unit conversions)

Explanation: The formula calculates how far the vehicle travels per minute based on tire circumference and RPM, then converts to miles per hour.

3. Importance of Wheel Speed Calculation

Details: Accurate speed calculation helps with gear ratio selection, speedometer calibration, and performance tuning.

4. Using the Calculator

Tips: Enter the engine RPM and tire diameter in inches. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure tire diameter?
A: Measure from the ground to the top of the tire when properly inflated, or use the tire size code (e.g., 235/75R15 means ~29" diameter).

Q2: Does this account for gear ratios?
A: No, this assumes a 1:1 gear ratio between engine and wheels. For accurate results, use wheel RPM rather than engine RPM.

Q3: Why 1056 as the conversion factor?
A: It combines conversions from inches to miles (63360) and minutes to hours (60): 63360/60 = 1056.

Q4: Can I use this for metric units?
A: No, this formula is for inches and miles. For km/h, use: (RPM × π × TD × 60) / 100,000 where TD is in meters.

Q5: How accurate is this calculation?
A: It's theoretically accurate but doesn't account for tire slippage, deformation, or load effects.