Why Downshift When Overtaking?

[Paula]

Downshifting during overtaking is done to obtain greater torque and improve acceleration. Here is relevant information: 1. The moment you upshift, the engine speed immediately decreases, but the vehicle speed remains unchanged. At the same time, since the transmission ratio becomes smaller, the torque output from the engine to the wheels also decreases. After completing the upshift, you accelerate by pressing the throttle, but due to the reduced torque output, the vehicle accelerates more slowly. 2. The moment you downshift, the engine speed immediately increases, but the vehicle speed remains unchanged. Simultaneously, as the transmission ratio becomes larger, the torque output from the engine to the wheels also increases. After completing the downshift, you typically reduce speed by easing off the throttle (so-called deceleration downshifting).

[PaisleeLynn]

Downshifting when overtaking is actually to increase the engine RPM, providing greater torque for faster acceleration to surge past. I often drive on the road, and if you're in a higher gear with low RPM when you step on the gas, the acceleration isn't as quick, potentially requiring prolonged parallel driving with adjacent vehicles, which increases risk. Dropping to a lower gear, say from fifth to fourth, instantly livens up the engine, delivering more power and making the car feel more energetic, enabling swift overtaking to shorten the dangerous distance. This isn't just crucial for manual transmission cars; automatics are the same—downshifting in manual mode achieves the same effect. The key is rapid acceleration to minimize time spent in the opposing lane, which is vital for safety, especially on mountain roads or narrow paths. Developing this habit makes driving more composed and less prone to accidents.

[BentleyRose]

From years of driving experience, I've learned that downshifting when overtaking is primarily to enhance safety and efficiency. Cruising in higher gears saves fuel but lacks explosive power, while dropping a gear allows the engine to operate in a higher RPM range, generating greater acceleration. This enables overtaking to be completed in just a few seconds, rather than slowly creeping past. For example, on highways, if you don't downshift and remain parallel to the car in front for too long, there's a risk if another vehicle suddenly changes lanes. After downshifting, the throttle response becomes quicker, allowing the car to surge forward and reducing collision risks. This applies to all types of vehicles: manual transmissions require manual gear changes, while automatic transmissions can trigger kickdown by pressing the accelerator deeply. This technique is particularly useful during emergency overtaking or uphill climbs, helping to avoid dangers caused by insufficient power.

[McLevi]

I think downshifting for overtaking is because lower gears can amplify the engine's torque for rapid acceleration. For example, in higher gears, the engine runs at lower RPMs, making acceleration feel sluggish - it takes forever to pass. Dropping a gear instantly raises the RPM, making the engine deliver more power. Step on the gas and the car surges forward. This reduces overtaking time, letting you dart past quickly to minimize risk. It's especially important for manual transmission cars - once you're familiar with the operation, it becomes second nature. Developing this habit makes driving smoother and safer.