Can You Keep Using the M Gear on the Highway?
3 Answers
The M gear in a transmission is the manual shifting mode. When the vehicle is in M gear, it operates similarly to a manual transmission mode, but without the need to press the clutch. The driver can shift gears appropriately based on the engine speed and vehicle speed. Automatic transmission cars have gears such as R, P, D, N, L, and S. The specific usage is as follows: R gear: Used for reversing, also known as the reverse gear. Note that the car must come to a complete stop before shifting into R gear. P gear: Used for parking, meaning the engine stops working, hence many people refer to it as the parking gear. D gear: Primarily used for driving the car forward, known as the drive gear, and is the basic gear for automatic transmission cars. N gear: Similar to the neutral gear in manual transmissions, with no difference in principle. It can be used when approaching a red light. L gear: A low gear used for uphill driving or overtaking. S gear: The sport mode, allowing free switching among all gears.
As an experienced driver who has been driving for many years, I think using the M gear (manual mode) on the highway isn't impossible, but it's really unnecessary to use it all the time. The M gear is a manual mode that allows you to shift gears yourself, giving a sense of control, which is great for climbing hills or overtaking for some fun. However, on the highway, where speed is generally stable, the automatic transmission's D gear will automatically match the optimal gear, saving fuel and hassle. I've tried using the M gear a few times on long trips, only to end up with higher RPMs, increased fuel consumption, and an annoyingly loud engine, which affected both my mood and my wallet. The best approach is to switch back to D gear during highway cruising. It's fine to play around with the M gear occasionally, but always maintain a safe distance and avoid getting distracted by fiddling with the gear stick. Driving is all about smoothness and natural flow. On the highway, the goal is to get from point A to point B safely—using the right tool for the job is what matters most.
From a technical standpoint, using the M mode (manual mode) for extended periods on highways is completely feasible, as the transmission can handle it. The key issue is efficiency: M mode requires manual gear control, and during steady-speed highway cruising, higher gears are more fuel-efficient, while D mode (drive mode) automatically shifts to the highest gear to maintain low RPMs. If the M mode is set too low, higher RPMs will increase fuel consumption and engine wear. For example, I tested that at 120 km/h, M5 gear maintains 2000 RPM, but M3 gear shoots up to over 3000 RPM, resulting in louder noise and higher costs. Automatic transmissions are designed with intelligent logic to adapt to various road conditions. On highways, D mode is the optimal choice, while switching to M mode offers more flexibility during dynamic driving. Combining both modes balances driving pleasure and daily practicality.
