1. What is a Gear Ratio Wheel Speed Calculator?

Definition: This calculator estimates vehicle speed based on engine RPM, wheel diameter, gear ratio, and axle ratio.

Purpose: It helps automotive enthusiasts and mechanics determine theoretical vehicle speed for given drivetrain configurations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Vehicle speed (mph)
• \( RPM \) — Engine revolutions per minute
• \( WD \) — Wheel diameter (inches)
• \( GR \) — Gear ratio (unitless)
• \( AR \) — Axle ratio (unitless)
• \( 1056 \) — Conversion factor (combines unit conversions)

Explanation: The formula calculates how fast the wheels turn based on engine speed and gear reductions, then converts this to miles per hour.

3. Importance of Speed Calculation

Details: Accurate speed estimation helps with gear selection, performance tuning, and verifying speedometer accuracy.

4. Using the Calculator

Tips: Enter engine RPM, wheel diameter (measured from ground to top of tire), gear ratio (transmission gear), and axle ratio (differential). Default axle ratio is 1.0.

5. Frequently Asked Questions (FAQ)

Q1: What's the 1056 constant in the formula?
A: It combines unit conversions (inches to miles, minutes to hours) and π/12 simplification.

Q2: How do I measure wheel diameter accurately?
A: Measure from ground to top of tire with proper inflation and vehicle weight on wheels.

Q3: Does this account for tire slip or deformation?
A: No, this calculates theoretical speed. Actual speed may vary due to traction conditions.

Q4: What if I have an overdrive gear?
A: Use the overdrive ratio (typically 0.6-0.8) as your gear ratio when in overdrive.

Q5: Why is axle ratio included separately?
A: Some vehicles have multiple axle ratio options, so it's kept as a separate variable for flexibility.