https://youtu.be/hODk5o9a5Qg
Is It Okay To Start In Second Gear?
<以下引用＞
Should you start from a stop in second gear?
Drivers have various reasons for starting in second gear, especially with a manual transmission. Perhaps first gear is too short, or snowy road conditions require lighter acceleration to avoid spinning the tires.
But is that a good idea?
Never fear because Jason Fenske of Engineering Explained is here to tell us about when it may make sense to start in second gear. He also takes the time to explain the differences between manual and automatic transmissions for a closer look at what's going on with your transmission and clutch.
Jason sees one scenario where starting in second gear truly makes sense for a car with a manual transmission. That's if a car is heading downhill from a dead stop. In this scenario, the momentum is already helping the car accelerate, and that makes for an easy transition to second gear. A first-to-second shift would be incredibly short going downhill. So, it makes sense.
Other times, it may seem like a second-gear start is easier, but there's more going on to upset the process, specifically, the clutch. Jason uses a basic flywheel and clutch demonstration to prove the point. For example, say the engine speed is at 1,000 rpm while the clutch is disengaged. In this scenario, in first gear, the car only needs to reach 5 mph to fully engage the clutch and stop it from slipping. In second gear, the car must reach 10 mph, which means the clutch will slip much more as the car accelerates. Ultimately, this will put more wear on the clutch
It's not the worst thing for the clutch (it's designed to handle slipping, after all), but the best practice is to keep RPMs low to avoid wheel spin.
With an automatic transmission, it's a different story. Since a torque converter handles power delivery from the engine to the transmission, there's less at stake for second-gear starts. As the flex plate spins, it forces fluid to one side of the torque converter, which tells a spline to send power to the transmission. It's a totally fluid coupling, and since there's no clutch plate to wear down, it doesn't pose a real risk. Most automatic transmissions have a W (Winter) mode that starts off in second gear to help prevent the tires from spinning on slick pavement.
So, for most drivers, starting in second gear is really no issue. Those driving a vehicle with a manual transmission, however, should brush up on their footwork.
Should you start from a stop in second gear?
