What is the minimum speed for 3rd gear?

[StKing]

3rd gear speed should not be lower than 20Km/h, with the corresponding speed range for 3rd gear being 20-40km/h. Gear introduction: 1st gear: Starting gear, used for vehicle launch. It has similar gear ratio and performance to reverse gear, thus not suitable for prolonged high-speed operation. Generally, you can shift to 2nd gear once the vehicle gains momentum. 2nd gear: Passing gear, mainly used for navigating complex road conditions and handling difficult situations, such as sharp-angle (right-angle) turns without special obstacles, crowded urban areas, steep slopes, and bumpy roads. 3rd gear: Transition gear, primarily used for low-speed urban driving. Depending on circumstances, it can easily transition up to 4th gear for acceleration or down to 2nd gear for deceleration. 4th gear: Cruising gear, mainly used for prolonged high-speed driving and economical operation. Most vehicles achieve their most fuel-efficient speed in the low-speed range of 4th gear. 5th gear: High-speed gear, mainly used for long-distance highway driving.

[VonLogan]

When I was learning to drive, my instructor always emphasized the importance of timing when shifting gears in a manual transmission. The third gear is most afraid of low speed, generally not lower than 20 kilometers per hour, otherwise the engine will shake violently or even stall. I made this mistake when I was stuck in traffic in the city at the beginning, crawling slowly in third gear, and the car suddenly shook, which gave me a fright. Later, I developed a habit: when the speed drops below 15 kilometers, quickly shift down to second gear to avoid lugging the engine. Beginners should practice listening to the engine sound or watching the tachometer, keeping it above 1500 RPM for safety. Regularly checking spark plugs and the fuel system can also prevent problems. These small details can make driving smoother and save on repair costs.

[Flores]

Having driven for over a decade, I have experience with gear control. When in third gear with a manual transmission, avoid letting the speed drop below 25 km/h, with 20 km/h being the absolute minimum tolerance. Otherwise, the engine will be under excessive load, leading to accelerated wear on components. I often advise friends that maintaining engine RPM between 1800 and 2000 is ideal—providing sufficient power, fuel efficiency, and protecting the engine. Once, on a steep slope, I forgot to downshift and drove at 15 km/h in third gear, causing the engine to roar loudly, wasting fuel and damaging the cylinders. In daily driving, it's crucial to shift gears promptly according to road conditions—don't cut corners for convenience. Maintaining good driving habits can extend engine life and reduce repair costs.

[DiJoshua]

I've repaired many cars, and the most common issue is damage caused by low speed in high gear. For manual transmissions, never let the 3rd gear drop below 1500 RPM or 20 km/h. Too low RPM leads to incomplete combustion and accelerated carbon buildup. This easily causes engine shaking, stalling, and even spark plug damage. I recommend drivers pay attention to the tachometer and avoid letting the engine labor too much, otherwise pistons and connecting components will wear out quickly with expensive repair costs. Doing this occasionally is acceptable, but habitual driving like this harms the engine and requires part replacements. Regular oil and filter changes help prevent premature aging and ensure driving safety.