Seen many videos of fast cars (mustangs especially lol) accelerating in a straight line and then losing control and going into the curb/crowd. What would cause it to do that when the wheels are just pointed straight ahead?
How does one prevent or control this?
In: Engineering
The cars are usually powered by the back wheels.
The cars are so powerful that when the driver pushes the pedal all the way down the back wheels spin faster than the car is travelling.
When the wheels are spinning faster than the car is traveling they lose traction (grip).
Traction (grip) is what keeps the car going in a straight line.
They have so much power that one (or both) of the tires loses grip and sends the car in an unpredictable direction.
This is worse on cars like Mustangs that have solid rear axles (as opposed to independent suspensions), one tire going over a bump or something affects the other tire.
You prevent this by having bigger and “stickier” tires that have more grip, as well as warming your tires. If you watch videos of drag racing you’ll usually see them burning out on purpose, this is to warm the tires.
There are also tire warmers used pre-race in some racing applications, literally electric blankets for your tires.
Let’s take a mustang as an example.
A mustang is a rear wheel drive. This means p o w e r from the engine is transmitted to the rear tyres, which spin and move the car forward. This usually fine.
When you send too much power to the wheel and there is not enough traction to move the car forward, the tyre spins instead of moving the car.
During these uncontrolled spins, the tyre will pick up small amounts of traction along the way and this may not always be in a perfectly straight line. This causes the car the veer to one side and slide the back out.
It may appear that they are going in a perfectly straight line but any minute shift in the steering wheel will alter the trajectory and send the car towards a spin.
If the driver keeps the power on and the tyres keep spinning then they will just slide out from under the car as they have no grip. Straight line now becomes sideways and much easier to lose control.
Typically you only see this in rear wheel drive cars as other drivetrains will lose grip and behave differently
What you’re describing occurs when a rear wheel drive car (like a Mustang) spins both its rear wheels. When this happens, the rear of the car will slide (left or right) and turn the car. When this happens the front of the car no longer points down the road, but rather towards a sidewalk or whatever and drives into it. The best way to prevent this is to keep the rear wheels from spinning. You can also counter steer by turning the steering wheel in the opposite direction (keep the front wheels pointing straight down the road). This is can easily get out of hand if you don’t know what you’re doing.
What happens is something (driver turning the wheel, pothole, bump, so on) causes the wheels to no longer be pointed straight ahead.
And at high speeds, this is more of an issue because of how much momentum you have. It creates a smaller margin for error where that slight turn of the wheels can cause you to flip.
Cars might be pointed perfectly straight but the road may not be perfectly even.
Small bumps or dips in the road can upset the balance of the vehicle, and at high speeds that could be enough to send the car left and right. Good reflexes and knowing how to properly counter-steer, and apply brakes/throttle should be able to correct this.
But let’s be honest, most guys doing this aren’t exactly doing high speed racing regularly and are most likely panicking once the car starts pitching one way and not properly correcting for it.
Roads are rarely even. The surface roughness varies from spot to spot. While it looks level, there may be a slight camber (side slope) and unevenness – some spots higher or lower than others. While it “looks” straight and even, to a tire and a car, it isn’t. Even a good driver cannot hold a steering wheel absolutely rigid and there is always mechanical variations in the steering, suspension and tire surfaces. When a car is trying to accelerate rapidly and/or has achieved fast speeds, these small variations can cause rather great effects. At 30 km/h, these are rarely problematic but at 300km/h small variations (even in things like wind direction or speed) can cause a car to go unstable.
Multiple things you can do to prevent this, for starters, don’t drive a car that has more horsepower and torque than you’re comfortable with.
You want to avoid applying full throttle. Have suitable tires for conditions. Drive cautiously when the road is wet.
If this does happen, your best bet is to release the accelerator.
The videos you see on the Internet of people crowd surfing is usually due to weight shift. Momentum that the driver doesn’t know how control.
The rear wheels are getting too much power for the amount of traction they have so they spin freely and can drift to either side. It’s like hydroplaning without the water. One side will suddenly get traction and the car will do something the driver doesn’t expect and they crash before they get it back under control.
To prevent it you either: use grippy racing tires that can keep up with your torque, know how to handle your specific car at max, or just leave the traction controls on and don’t try to learn how to do burnouts in the middle of the crowded road.
It’s not the car that lost control, its the driver. In virtually every case the car likely had it’s driver aids turned off. When you accelerate really hard in a car with alot of power it will break traction and spin it’s wheels. With all driver aids off, it is up to the driver to manage throttle and steering to keep the car going in the direction it needs to go. As the wheels spin they will grab and lose traction unequally and at unpredictable times, the driver needs to be able to quickly countersteer the car to keep it in line. Many(most) people do not have the skills needed to keep a very powerful car under control without driver aids. End result, they lose control and hit something.
tl;dr: People are dumb and turn off the things in their car that stop their dumb actions from having real world consequences, then do dumb things in their car and encounter real world consequences.
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