1. What is the Gear Ratio MPH Equation?

The Gear Ratio MPH equation calculates vehicle speed based on engine RPM, tire circumference, and gear ratio. It's essential for automotive enthusiasts, mechanics, and engineers to understand vehicle performance characteristics.

2. How Does the Calculator Work?

The calculator uses the gear ratio to MPH equation:

Where:

• \( RPM \) — Engine revolutions per minute
• \( C \) — Tire circumference in inches
• \( GR \) — Gear ratio (dimensionless)
• 60 — Conversion from minutes to hours
• 63360 — Conversion from inches to miles (5280 feet/mile × 12 inches/foot)

Explanation: The equation converts engine rotation speed to vehicle speed accounting for gear reduction and tire size.

3. Importance of Gear Ratio Calculation

Details: Understanding the relationship between RPM and speed helps in vehicle tuning, transmission selection, and fuel efficiency optimization.

4. Using the Calculator

Tips: Enter RPM (typically 1500-7000 for most vehicles), accurate tire circumference (measure or use manufacturer specs), and the complete gear ratio (including final drive ratio if applicable).

5. Frequently Asked Questions (FAQ)

Q1: How do I measure tire circumference?
A: Measure from ground to axle center (radius) and multiply by 2π, or roll the tire one revolution and measure distance traveled.

Q2: What's a typical gear ratio?
A: Varies by vehicle: 3-4:1 for performance cars, 2-3:1 for economy cars, and higher for trucks.

Q3: Does this account for torque converter slip?
A: No, this calculates theoretical speed. Actual speed may be slightly lower due to transmission slip.

Q4: Can I use this for bicycles?
A: Yes, the same principle applies to any wheeled vehicle.

Q5: How accurate is this calculation?
A: Very accurate if inputs are precise, but doesn't account for tire deformation, slip, or wind resistance.