1. What is Gear Ratio?

Gear ratio (GR) is a key parameter in drag racing that represents the relationship between the rotational speeds of two or more interlocking gears. It determines how many times the engine must rotate to turn the wheels once.

2. How Does the Calculator Work?

The calculator uses the gear ratio formula:

Where:

• \( RPM \) — Engine revolutions per minute
• \( tire\_dia\_in \) — Tire diameter in inches
• \( MPH \) — Vehicle speed in miles per hour
• 336 — Constant that combines unit conversions

Explanation: The equation calculates the gear ratio needed to achieve a certain speed at a given RPM with specific tire size.

3. Importance of Gear Ratio in Drag Racing

Details: Proper gear ratio is crucial for optimizing acceleration and top speed in drag racing. It affects how quickly the car can reach its optimal power band.

4. Using the Calculator

Tips: Enter engine RPM, tire diameter in inches, and desired speed in MPH. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical gear ratio for drag racing?
A: Most drag cars use ratios between 3.50:1 and 4.10:1, depending on the vehicle and track conditions.

Q2: How does tire size affect gear ratio?
A: Larger tires effectively increase the gear ratio (make it numerically lower), while smaller tires decrease it.

Q3: What's the 336 constant in the formula?
A: It combines unit conversions (5280 feet/mile × 12 inches/foot ÷ 60 minutes/hour ÷ π).

Q4: Should I use this for street cars?
A: While the calculation works for any vehicle, street cars need to balance acceleration and highway cruising.

Q5: How does gear ratio affect ET?
A: Proper gearing keeps the engine in its power band throughout the run, optimizing elapsed time (ET).