What speed is safe for 4th gear without damaging the car?
2 Answers
Driving in 4th gear at 70 km/h will not harm the car, as long as the speed is kept below 70 km/h. Here is some relevant information: 1. P (Parking) gear, starting gear: When the car is parked and not in use, the gear should be in this position, where the wheels are mechanically locked to prevent rolling. The vehicle must be completely stopped before shifting to P gear, otherwise the mechanical parts of the automatic transmission may be damaged. 2. R (Reverse) gear: Used for reversing. Unlike manual transmission cars, automatic transmission cars do not have a clutch pedal for semi-engagement, so special attention must be paid to the control of the accelerator pedal when reversing. Usually, the safety button on the shift lever must be pressed before moving the lever to the "R" position.
Having driven manual transmission cars for decades, I believe the speed at which driving in 4th gear doesn’t harm the car mainly depends on the engine RPM. The most comfortable range is between 1500 to 2500 RPM. Going too low, below 1200 RPM, can cause lugging and engine damage, while exceeding 3000 RPM may increase wear. A reasonable speed is around 60 to 80 km/h, varying by car: for small-displacement cars, don’t exceed 70 km/h, while larger-displacement cars can go slightly higher to 85 km/h. Also, pay attention to road conditions—on inclines or when carrying heavy loads, keep the RPM above 1800 for safety. Listen for smooth engine sounds and avoid prolonged operation at extreme RPMs to protect the transmission. Regular maintenance also helps.
