Wouldn’t the traction be the same in any gear, and the point at which you lose traction be the same regardless?
Edit: Thanks for all the explanations, I think I understand now. 🙂
In: 7
In 2nd gear, the torque put out at the wheel should be lower and more easily controlled by the driver. The traction is the same but the likelihood of slipping is less with a more controlled application of torque.
The higher the gear the less torque, torque is rotational power, so if you’re spinning your wheels trying to get moving in first, second has less torque and is less likely to spin the wheels from a stand still.
The point of gears in a car is to multiply the amount of torque provided to the wheels. The engine makes a certain amount of torque, and the gears multiply that to allow the car to drive. Your traction devices (tires) can apply a certain amount of force to the road, and no more before they start to slip, so in a low traction situation, you want to apply only as much torque as the tires can apply to the road.
In 1st gear, the gear ratio will be the shortest of all (numerically higher), and will provide the most torque to the wheels. 2nd gear will be the next lower, and so on through your gear box.
By starting in second, you are lowering the torque multiplication and as such, the amount of torque applied to the road through the tires. You may still spin the tire if you apply heavy or full throttle, but the likelihood of doing so at part throttle is greatly reduced. Another benefit is that starting in a higher gear will make it more difficult for the engine to increase its speed (RPM), which will keep you in the lower end of the torque curve longer.
Picture three gears that you can swap out from one another, all with the same space between sprockets. One is large, the second is medium sized, and the third is small. To the left is a handle you can grab with your fingers and spin to cause the left most gear to spin. To the right is a smaller shaft the second gear helps drive perpendicular to how the gears touch. The faster this shaft turns, the more speed you get.
If you want the most speed in the quickest amount of time, you would stick the large gear first, and connect the smallest gear with the speed shaft. Why? Because for each fraction of a turn of the large gear, you would be able to make the smaller gear turn with a much greater speed due to being smaller with a less amount of sprockets on it to push. This is 1st gear.
Okay, so while it keeps that momentum going, you decide your arm is getting tired, so you swap out the large gear with a medium one so you don’t have to push as hard. The speed slightly declines when you do this, but with less turns overall you can maintain the same speed. 2nd gear.
3rd gear would be to swap the small and large. Suddenly, you have to push really fast to get that little gear to get the large one spinning, but it works if the handle you’re spinning with your hand already is spinning fast.
So, 2nd gear is the best compromise between harder startup speed, and controlling that speed safely when your hand might slip off the handle since it’s slick.
You can drive in any gear in the snow or low traction conditions. The reality of driving is that lower gears result in more instantaneous accidental acceleration for small pedal presses. If you blip the throttle in 1st, your car will attempt to rocket off and your wheels will simply spin. If you try to dump the gas pedal in third, your car won’t go anywhere at a low rev range because the torque is so low.
It’s all about how the car responds to your throttle press, and it responds massively and quickly in 1st, and much more slowly and forgivingly in 2nd. Any gear higher than that and you might have stalling issues.
I think what you’re looking for is an explanation of the “threshold of motion” which is the point where the tires slip and go from static to kinetic friction. On certain snow and ice conditions the available static friction is low and kinetic even lower. So your car is trying not to apply very much torque to the tires. And starting in second gear is easier for the vehicle to very gently apply the power to the tires in automatic transmissions because of how they function internally.
Let me tell you about a bunch of Americans who have no idea what you’re talking about.
Imagine your legs were eight feet long. You’d almost never slip in the snow because it would be so hard to get long legs like that to slip, whereas if they were a foot long they would slip continuously, even using the same amount of power.
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