Although I have a heavy box-shaped car, I was thinking about the Mercedes G63 specifically. That is a powerful engine on a non-aerodynamic car, what happens if you take it over 100mph and get hit by a gust of 60mph wind? My car gets literally pushed around lanes during heavy winds at highway speeds, has anyone ever even gotten a G63 past 150mph?
In: Physics
First we need to understand what forces a wind gust will put on a G63.
The G63 has a smaller front and larger rear, so the rear will experience more force from a crosswind than the front. The net result is a force of *rotation* on the car that makes it rotate *into the wind*. This is an effect called [weathervaning](https://en.wikipedia.org/wiki/Weather_vane). In other words, the car wants to rotate into the wind, since it’s most aerodynamic when the wind is coming head-on.
You can see an extreme example of this [here](https://youtu.be/bdl94J3AxZY?si=vMQN9CWkkKt3KGtH&t=42), note how the car actually starts off *rotating*, with the rear of the car being affected by the wind more than the front; it doesn’t get blown directly sideways like you might have guessed.
Let’s say a G63 is traveling at speed and gets hit by a strong wind gust from the right (the wind is traveling left). As the wind gust puts a rotational force on the G63, it will rotate right, into the wind, by having its left wheels rotate slightly faster than its right wheels. This is easy for the wind to do at speed, since all of the static friction in the drivetrain has already been overcome, and cars are designed for their left and right wheels to rotate at different speeds as they turn.
With the car stopped and in neutral, the static friction in the drivetrain (the wheel bearings, differentials, etc.) will prevent the car from rotating up to a point, but if the wind is strong enough, it will cause the car to rotate into the wind. (For this to work at a stand-still, the differentials would have to allow the wheels to rotate in opposite directions, that’s not always the case.).
If the car is in park, the wheels are prevented from rotating, and the wind will just cause the car to lean, until the wind is strong enough to overcome the static friction between the tires and the road or to flip the car.
[Here’s another example of a semi getting blown around](https://www.youtube.com/watch?v=bj-dDQ9UJ7U), note how it’s causing the whole vehicle to rotate into the wind and the driver is correcting for it by steering in the same direction as the wind is going.
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