What is the appropriate speed for third gear, and what is the optimal speed for fourth gear?
2 Answers
When downshifting from fourth to third gear, the speed should be reduced to around 30 km/h. First gear is used for starting, with speeds generally ranging from 0-5 km/h; second gear corresponds to speeds of 5-20 km/h; third gear corresponds to speeds of 20-40 km/h; fourth gear corresponds to speeds of 40-60 km/h; and fifth gear corresponds to speeds of 60-100 km/h. Generally, the optimal gear-shifting timing for most cars is when the engine reaches 2000 r/min, preferably not exceeding 2500 r/min. For high-displacement, high-power engines, the maximum efficiency range is often delayed, so shifting around 3000 r/min may be considered. Different vehicles have varying engine and transmission performances. Drivers can determine the right shifting moment by listening to the engine sound. A dull engine sound usually indicates the need to upshift, as driving in a lower gear increases engine strain, fuel consumption, and negatively impacts both the engine and transmission. Additionally, downshifting is necessary when the engine speed drops below approximately 1500 r/min. Gear-shifting techniques: Smoothness: When engaging a new gear, the clutch should be released gradually while simultaneously applying the throttle for a smooth transition. Accuracy: Body movements should be coordinated and precise to avoid jerky shifts, which degrade the driving experience. Speed: Quick gear changes enhance vehicle smoothness, reduce kinetic energy loss, and improve fuel efficiency. Timeliness: Shift gears at the right moment—neither too early nor too late—to ensure optimal performance.
I commute daily with a manual transmission car, driving on both intercity roads and urban streets. I've found that third gear works well between 20 to 40 km/h, especially when maintaining a steady speed of 25 to 35 km/h in the city. The engine stays just above 2000 RPM, providing a smooth and stable ride without any jolting. If the speed drops below 20 km/h or in heavy traffic, shifting to second gear is better. When accelerating past 40 km/h, such as after passing a traffic light, immediately shifting to fourth gear saves fuel and ensures safety. Fourth gear performs best within the 40 to 60 km/h range, cruising comfortably at 50 km/h near highway entrances, with light engine noise and low fuel consumption. Avoid forcing fourth gear at low speeds like 30 km/h, as it causes engine shuddering and wastes fuel. Based on practical experience, proper gear shifting can reduce fuel consumption by about 10% and also prolong engine life.
