1. What is the MPH Calculation?

The MPH (miles per hour) calculation determines vehicle speed based on engine RPM, tire size, and gear ratios. This is essential for performance tuning, gear selection, and understanding vehicle dynamics.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( RPM \) — Engine revolutions per minute
• \( \text{tire circumference} \) — Tire circumference in inches
• \( \text{gear ratio} \) — Transmission gear ratio (unitless)
• \( \text{final drive ratio} \) — Differential gear ratio (unitless)
• \( 63360 \) — Conversion factor (inches in a mile)

Explanation: The equation converts engine RPM to wheel RPM using gear ratios, then calculates distance traveled per hour based on tire size.

3. Importance of MPH Calculation

Details: Accurate speed calculation helps in gear selection for racing, fuel efficiency optimization, and verifying speedometer accuracy.

4. Using the Calculator

Tips: Enter RPM (typically 1000-7000 for most vehicles), tire circumference (can be calculated from tire size), and both gear ratios. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How do I find my tire circumference?
A: Measure your tire's diameter and multiply by π (3.1416), or use online tire size calculators that convert tire size markings to circumference.

Q2: What's a typical final drive ratio?
A: Passenger cars typically range from 2.73 to 4.10, while performance vehicles may have higher ratios (3.55-4.56).

Q3: Why multiply by 60 in the formula?
A: This converts "revolutions per minute" to "revolutions per hour" for the MPH calculation.

Q4: How accurate is this calculation?
A: Very accurate for theoretical speed, though actual speed may vary slightly due to tire slippage, inflation, and wear.

Q5: Can I use this for different units?
A: For km/h, replace 63360 with 100000 (cm in a km) and use tire circumference in centimeters.