Can a car stay in S gear on the highway?

[DeDallas]

Cars should not stay in S gear on the highway. Because using S gear continuously on the highway can damage the vehicle. S gear, also known as the car's sport mode, delays the shifting timing when engaged. This keeps the engine at higher RPMs for longer periods, allowing the car to operate at high RPMs in lower gears to achieve greater output torque. Generally, for automatic transmission cars on the highway, using D gear is sufficient. This is because highway speeds typically range between 90-120 km/h, and with moderate traffic, there's less need for frequent overtaking, rapid acceleration, or hard braking. In such conditions, driving in D gear ensures safer, smoother, and more fuel-efficient operation. S gear is best used when overtaking on the highway. Since overtaking at high speeds requires quick acceleration, engaging S gear provides greater output torque, making the maneuver quicker and safer.

[OAutumn]

Using the S mode continuously on the highway is certainly possible, but based on personal experience, it's not ideal. The S mode is designed to keep the engine RPM in a higher range, which indeed provides faster acceleration response—making overtaking thrilling. However, fuel consumption increases significantly in this mode compared to driving in D mode, leading to higher fuel costs. Moreover, maintaining high engine RPM for extended periods at steady highway speeds may accelerate wear on components like the transmission or pistons, increasing maintenance costs. When driving on the highway, I prefer using D mode for its smoothness, fuel efficiency, and lower noise. I only switch to S mode occasionally for quick acceleration when overtaking, then switch back immediately afterward. This approach protects the car and saves money, making long-distance driving more worry-free.

[AustinLynn]

As an average driver who frequently uses highways, I find it unwise to constantly drive in Sport (S) mode. While S mode delivers strong power output and is exhilarating to drive, maintaining high RPMs for extended periods on highways inevitably leads to a surge in fuel consumption—emptying the tank faster and draining the wallet quicker. Additionally, the increased engine load creates a loud, roaring noise that becomes irritating over time, affecting driving comfort. I recommend using Drive (D) mode for most highway cruising—it’s smooth, effortless, and sufficient. Only switch to S mode briefly when climbing steep slopes or overtaking, then return to D mode afterward. This ensures your car stays healthy, maintenance costs remain low, and it’s even more eco-friendly.

[EverlyLee]

After years of driving, I've found that constantly using S mode on highways consumes too much fuel and puts extra strain on the engine. Prolonged use of S mode leads to higher RPMs, increased wear, and potentially shortens engine lifespan, resulting in costly repairs. Maintaining steady speed with D mode is perfectly stable on highways - there's no need for unnecessary gear changes. I recommend sensible gear selection to save fuel costs while ensuring safe driving.