25 June 2025 | Leave a comment Numerical values of gear ratios The gear ratio is the ratio of the speed of rotation of the gearbox input shaft to the speed of rotation of the output shaft. A lower gear ratio indicates a higher gear, which provides higher speed and less torque. A higher gear ratio indicates a lower gear, which provides lower speed and more torque. Here are examples of gear ratios used in various automatic transmission gears: Forward gears * First gear: 2.5:1 – 4:1 * Second gear: 1.5:1 – 2.5:1 * Third gear: 1:1 – 1.5:1 * Fourth gear: 0.75:1 – 1:1 * Fifth gear: 0.65:1 – 0.9:1 * Sixth gear: 0.55:1 – 0.8:1 * Seventh gear: 0.45:1 – 0.7:1 * Eighth gear: 0.35:1 – 0.6:1 Reverse gear * Reverse: 2.5:1 – 4:1 Effect of Gear Ratio on Performance Gear ratio has a significant impact on vehicle performance: *Acceleration: Lower gear ratios provide sharper acceleration because the engine can spin at a higher speed, producing more torque. *Top Speed: Higher gear ratios allow the vehicle to achieve higher top speeds because they reduce engine speed and reduce drag. * Fuel Economy: Higher gear ratios improve fuel economy at high speeds because the engine can run at lower speeds, burning less fuel. * Towing: Lower gear ratios are necessary for towing heavy loads as they provide more torque to overcome the additional drag. Selecting the optimal gear ratio The optimal gear ratios for a particular vehicle depend on a number of factors, including: * Motor size and power * Vehicle weight and aerodynamic drag * Intended type of use (urban, suburban, towing) Car manufacturers carefully select gear ratios to optimize performance, fuel economy and handling for different models. Thanks for reading!