1. What is a Tire Height Gear Ratio Calculator?

Definition: This calculator determines the optimal gear ratio based on engine RPM, tire height, and desired vehicle speed.

Purpose: It helps automotive enthusiasts and mechanics select proper gearing for performance or fuel efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GR \) — Gear ratio (unitless)
• \( RPM \) — Engine revolutions per minute
• \( TH \) — Tire height (inches)
• \( S \) — Vehicle speed (miles per hour)
• \( 1056 \) — Conversion constant (combines unit conversions)

Explanation: The formula calculates how many times the driveshaft must rotate to turn the wheels once at a given speed.

3. Importance of Gear Ratio Calculation

Details: Proper gear ratio selection affects acceleration, top speed, fuel economy, and engine longevity.

4. Using the Calculator

Tips: Enter engine RPM at cruising speed, measure actual tire height (not just sidewall numbers), and desired speed. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure tire height accurately?
A: Measure from ground to top of tire with vehicle weight on it and proper inflation.

Q2: What's a typical gear ratio range?
A: Passenger cars: 3.0-4.0, trucks: 3.5-4.5, performance vehicles: 3.5-5.0.

Q3: Why does tire height affect gear ratio?
A: Larger tires effectively create a higher (numerically lower) gear ratio.

Q4: What RPM should I use for calculations?
A: Use your engine's optimal cruising RPM (often 2000-3000 RPM for fuel efficiency).

Q5: Does this account for transmission gear?
A: No, this calculates final drive ratio. Multiply by transmission gear ratio for complete analysis.