What is the gear speed ratio?
2 Answers
Generally, high-revving engines in French cars follow a shift-up pattern of 20 km/h in 2nd gear, 40 km/h in 3rd gear, 60 km/h in 4th gear, and 80 km/h in 5th gear. For low-revving engines, the pattern is 10 km/h in 1st gear, 30 km/h in 2nd gear, 40 km/h in 3rd gear, 60 km/h in 4th gear, and 80 km/h in 5th gear. Additional information: The principle for deceleration and downshifting is to reduce speed first, then downshift, and skipping gears is allowed. In automatic transmission vehicles, speed and gear should correspond to each other. When the speed matches the gear, the vehicle's performance is at its optimal state, and the thermal efficiency of fuel is the highest. If the speed and gear are mismatched, such as high speed with low gear or low speed with high gear, it will not only increase fuel consumption but also cause damage to the engine and transmission, leading to irreversible harm to the vehicle. Therefore, it is essential to maintain the proper match between gear and speed while driving.
Driving a manual transmission for years has taught me that the speed matches best with gears based on the situation. In most cars, especially in daily commuting, first gear works from zero up to around 15 km/h for starting off smoothly. Shift to second gear when you're between 15 and 30 km/h, which handles city traffic nicely. Third gear fits speeds of 30 to 50 km/h, like cruising on residential roads. For higher speeds, say 50 to 70 km/h on highways, fourth gear is comfortable. Anything over 70 km/h works well with fifth or sixth gear to keep things efficient. Why this matters? Sticking to these ranges prevents the engine from laboring or screaming—it saves fuel and protects the car long-term. I learned the hard way when ignoring this led to stalling or wear in my first car; now I always listen to the engine hum or glance at the tachometer to stay in the optimal RPM range under 3000.
