1. What is Final Gear Ratio?

The Final Gear Ratio is the product of the transmission ratio and differential ratio. It represents the overall reduction between the engine's crankshaft and the drive wheels, affecting vehicle acceleration, top speed, and fuel efficiency.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Transmission Ratio — Gear ratio of the selected transmission gear
• Differential Ratio — Fixed ratio of the vehicle's differential

Explanation: The final ratio determines how many times the engine must rotate to turn the wheels once.

3. Importance of Gear Ratio Calculation

Details: Knowing the final drive ratio helps in understanding vehicle performance characteristics, choosing appropriate gear ratios for racing applications, and optimizing fuel economy.

4. Using the Calculator

Tips: Enter both transmission and differential ratios as positive numbers. Typical values range from 2.0 to 5.0 for transmission ratios and 2.5 to 4.5 for differential ratios in most passenger vehicles.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical final drive ratio?
A: For passenger cars, final ratios typically range from 9:1 to 15:1 in first gear, decreasing to 2:1 to 4:1 in top gear.

Q2: How does final ratio affect performance?
A: Lower ratios provide better acceleration but lower top speed, while higher ratios improve fuel economy at highway speeds.

Q3: Can I use this for motorcycles?
A: Yes, the same formula applies to any vehicle with a transmission and final drive system.

Q4: What about overdrive gears?
A: Overdrive gears have ratios less than 1:1, which when multiplied by the differential ratio result in a final ratio that reduces engine RPM at cruising speeds.

Q5: Where can I find my vehicle's ratios?
A: Transmission ratios are in the vehicle's service manual, while differential ratio is often stamped on the differential housing or listed in specifications.