Is It Necessary to Press the Clutch When Braking in a Manual Transmission?
2 Answers
When braking in a manual transmission, it is not always necessary to press the clutch. The key factors to consider are the vehicle speed, gear position, and engine RPM. Below are the relevant details: 1. The engine's power is transmitted to the gearbox through the clutch, and the gearbox changes the engine's RPM before transferring it to the wheels. The engine and wheels always rotate synchronously at a certain ratio; 2. For example, in 1st gear, the engine rotates 4 times while the wheels rotate once. After shifting to 2nd gear, the engine rotates 3 times while the wheels rotate once. Pressing the clutch disconnects the engine from the wheels, making them independent of each other. However, if the clutch is not pressed, the engine RPM, gear position, and vehicle speed must correspond; 3. The engine RPM has a lower limit, which is the idle speed. If the RPM falls below idle, the engine is prone to stalling. Therefore, the theoretical minimum speed for each gear is the vehicle speed when the engine is at idle. When the vehicle speed in a particular gear falls below this speed, the engine may stall. During deceleration, as long as the current vehicle speed is higher than the idle speed for that gear, there is no need to press the clutch. When braking in the current gear, as long as the engine RPM does not drop below idle, pressing the clutch is unnecessary.
For someone like me who has driven manual transmission cars for over 20 years, whether to press the clutch when braking really depends on the specific situation: during normal deceleration, such as slowing down from highway speeds to 40-50 km/h, there's no need to press the clutch at all—the engine can help control the speed and save fuel; but when coming to a complete stop or slowing down to very low speeds, like waiting at a red light at an intersection, you must press the clutch, otherwise the engine is prone to stalling, causing inconvenience. Once when I was driving in the rain, I braked hard without pressing the clutch, the car stalled and I almost rear-ended the car in front. Since then, I've remembered to adjust based on speed: don't press the clutch for light braking, but press it decisively for hard braking. In daily driving, developing this habit can extend the vehicle's lifespan and avoid excessive clutch wear. In short, you need to combine road conditions and experience to judge—drive a few more times and you'll naturally get the rhythm.
