What is the Difference Between S Gear and D Gear?
4 Answers
D gear and S gear differ in terms of their main functions, characteristics, and working principles. The specific details are as follows: Main Functions: D Gear: It is the most common gear in automatic transmission vehicles, allowing the car to automatically select the appropriate gear while moving forward. S Gear: It is the sports mode of the car. Characteristics: D Gear: One of the most common gears in automatic transmission vehicles, it is a type of forward gear that covers all forward gears in the car's automatic transmission. S Gear: When using S gear, the engine's fuel injection increases due to higher RPMs, resulting in greater power. Additionally, the suspension becomes stiffer than usual, reducing body roll during turns. Working Principles: D Gear: When the gear shift lever is placed in D gear, the hydraulic control system automatically engages the corresponding forward gear based on throttle opening and vehicle speed signals. The transmission shifts up or down within the forward gears as the output shaft speed and engine speed change, achieving automatic transmission functionality. S Gear: In S gear (sports mode), the transmission can shift freely, but the shift timing is delayed. This keeps the engine at high RPMs for a longer period, allowing the car to maintain low gear and high RPM operation for extended durations, thereby delivering greater torque output and acceleration.
I've been driving for over ten years, and D mode is the most commonly used automatic transmission setting. The transmission decides when to shift gears on its own, making the drive super smooth. S mode is totally different—engaging it is like giving the car a shot of adrenaline. The RPMs shoot up immediately, and the engine roars. It's especially thrilling when overtaking; just step on the gas, and the car surges forward. However, fuel consumption goes up. Last time I tried it on the highway, using S mode burned nearly two liters more fuel than D mode. Also, S mode is great for long downhill slopes—the transmission stays in lower gears, so you don't have to keep pressing the brakes, saving a lot on brake pads. For daily city commuting, D mode is the practical choice—easy on the mind and the wallet.
Last time I took my family on a mountain road trip, I finally understood the difference between these two gears. D mode is like a thoughtful butler, shifting up early to higher gears with the engine humming softly, providing a smooth and fuel-efficient ride. S mode is a completely different beast—it intentionally delays upshifting to keep the RPM in the most powerful range. When climbing steep slopes, switching to S mode makes a noticeable difference, giving the car much more pulling power. Here’s a cool fact: in S mode, the auto start-stop system automatically turns off, so the engine won’t shut down at red lights. However, I don’t recommend using S mode in rainy weather—the increased torque can easily cause wheelspin. Once, I stepped on the gas too hard on a wet road and triggered the ABS, which gave me quite a scare.
The mechanic taught me to understand it this way: D mode is like using an automatic pencil, where you press a little to get a little lead, saving effort but not writing quickly. S mode is like a manual pencil, where you can twist out as much lead as you want. The most noticeable difference in actual driving is during the initial acceleration phase. When you're first in line at a red light, starting in S mode can leave the cars behind far behind. However, the transmission computer becomes particularly sensitive in S mode, downshifting with just a slightly deeper press of the accelerator, making high-speed cruising less comfortable than in D mode. I've found that it's best to turn off the air conditioning when using S mode, otherwise, when the AC compressor kicks in, there's a noticeable lag in power.
