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> I also destroyed my transmission by putting it in park at high speed. Worth it. absolutely not worth it. modern cars (ie, anything with abs and disk brakes)

> I also destroyed my transmission by putting it in park at high speed. Worth it. absolutely not worth it. modern cars (ie, anything with abs and disk brakes) achieve maximum deceleration when you mash the brake pedal and allow the car to modulate the clamping force. using the emergency brake and putting the car in park just locks up the wheels. the whole point of abs is to avoid this. you destroyed your transmission to increase your stopping distance.

withinboredom 3y ago
This was most certainly not anywhere near a modern car. Further, it was a gravel road, which is a case where I'm not sure ABS brakes work better, but I could be wrong.
- leetcrew 3y ago
  the first key insight here is that brakes can generate much more friction against the wheel than the tire can against any surface you're driving on. this makes the tires the limiting factor for stopping distance, not the brakes. the only exceptions to this rule are very old (like pre-1980s) cars, cars that desperately need new brake pads, and brakes that have overheated from heavy use on a track or riding them down a long hill. the second key insight is that tires generate the most friction when they are allowed to slip only a small amount. different surfaces have different optimal slip amounts, but you never want to lock up the wheels completely. gravel does make a difference here. abs is typically tuned for optimal performance on pavement, so it's at least theoretically possible for a skilled human driver to outperform older abs implementations on gravel. the average driver panic stopping is very unlikely to beat abs though. being a lower traction surface, it's also much easier to lock up the wheels on gravel. there's no reason to use the ebrake and especially not to force the transmission into park unless you know for a fact that the main brake pads are failing. I'm sorry to completely beat you over the head with this explanation, but what you describe is extremely unsafe and I really hope no one reads that and tries it themselves in an emergency. the emergency stop SOP for any abs-equipped car is 1) fully depress the brake pedal, 2) focus on steering the car away from the immediate hazard or at least in a relatively straight line.
  - withinboredom 3y ago
    The issue is that I realized I wasn't going to stop in time while depressing the brakes, but just barely. That was when I pulled the e-brake and put the car into a spin, trying to burn energy. By that point, I was probably only doing 20-30mph. Thus I came to the train tracks almost parallel, but skidding along the road. My goal, as I was doing it, was to clip the train and get pushed along vs. shoved from the side. Then put the car in park to hopefully absorb as much of that impact as possible since I figured I might either die or lose consciousness. I wanted to be found on the road, instead of in the swamp on either side of the road. I was incredibly lucky that day, there is no doubt about it, but, I also did a lot of insane driving during that point in my life. I knew how to handle that car in a variety of conditions from rain, gravel, snow, and ice and any mix of them. Did I make the right decisions during those fleeting seconds? Possibly, possibly not. One thing I did have, was options. Options are something that has been taken away over the years through weird UX choices.
psunavy03 3y ago
You don't seem to understand the point of ABS brakes. The way to achieve maximum deceleration in a car IS to lock up the wheels. The reason ABS brakes exist is because when the wheels are locked, the car is sliding as opposed to rolling, which causes the car to skid instead of turn when you turn the steering wheel. Average drivers tend to struggle with this and end up spinning out of control. So ABS brakes pump the brakes rapidly as a compromise between controllability and stopping distance, which allows the average driver in an emergency to just "stomp and steer" instead of having to learn how to control a skid, which is a more advanced driving skill. But they do this at the expense of stopping distance, which is longer than if you just locked up the brakes. Putting the transmission in park was still unnecessary and probably useless. It's not designed for that force, so it didn't absorb any energy or help the car stop faster; it just blew up.
- kqr 3y ago
  I'm not sure this is true. Yes, steerability is the main benefit of ABS, but I think bringing wheels from a slight roll to skid absorbs more energy (through deformation of the rubber) then just skidding along would under the same time frame. I.e. ABS does marginally decrease stopping distance -- at least on asphalt -- compared to plain skidding friction.
- rootusrootus 3y ago
  > The way to achieve maximum deceleration in a car IS to lock up the wheels That isn't true. Dynamic friction for a tire is always less than static friction, as soon as the tires are sliding your stopping distance is going to get longer. A good driver used to be able to threshold brake better than a basic ABS setup, but that hasn't been true now for years. Modern ABS computers are quite advanced.
- outworlder 3y ago
  > The way to achieve maximum deceleration in a car IS to lock up the wheels. Very much untrue and it's a subject covered by school physics textbooks. The wheels may not lock up simultaneously(often don't) and that is the reason why ABS will monitor wheels individually. And, if you are doing that, might as well do it all the time, and that's traction control. ABS decreases stopping distance and increases controllability. It's a win win. These days you can't really do any better than ABS, "average" driver or not.

withinboredom 3y ago

This was most certainly not anywhere near a modern car. Further, it was a gravel road, which is a case where I'm not sure ABS brakes work better, but I could be wrong.

leetcrew 3y ago
the first key insight here is that brakes can generate much more friction against the wheel than the tire can against any surface you're driving on. this makes the tires the limiting factor for stopping distance, not the brakes. the only exceptions to this rule are very old (like pre-1980s) cars, cars that desperately need new brake pads, and brakes that have overheated from heavy use on a track or riding them down a long hill. the second key insight is that tires generate the most friction when they are allowed to slip only a small amount. different surfaces have different optimal slip amounts, but you never want to lock up the wheels completely. gravel does make a difference here. abs is typically tuned for optimal performance on pavement, so it's at least theoretically possible for a skilled human driver to outperform older abs implementations on gravel. the average driver panic stopping is very unlikely to beat abs though. being a lower traction surface, it's also much easier to lock up the wheels on gravel. there's no reason to use the ebrake and especially not to force the transmission into park unless you know for a fact that the main brake pads are failing. I'm sorry to completely beat you over the head with this explanation, but what you describe is extremely unsafe and I really hope no one reads that and tries it themselves in an emergency. the emergency stop SOP for any abs-equipped car is 1) fully depress the brake pedal, 2) focus on steering the car away from the immediate hazard or at least in a relatively straight line.
- withinboredom 3y ago
  The issue is that I realized I wasn't going to stop in time while depressing the brakes, but just barely. That was when I pulled the e-brake and put the car into a spin, trying to burn energy. By that point, I was probably only doing 20-30mph. Thus I came to the train tracks almost parallel, but skidding along the road. My goal, as I was doing it, was to clip the train and get pushed along vs. shoved from the side. Then put the car in park to hopefully absorb as much of that impact as possible since I figured I might either die or lose consciousness. I wanted to be found on the road, instead of in the swamp on either side of the road. I was incredibly lucky that day, there is no doubt about it, but, I also did a lot of insane driving during that point in my life. I knew how to handle that car in a variety of conditions from rain, gravel, snow, and ice and any mix of them. Did I make the right decisions during those fleeting seconds? Possibly, possibly not. One thing I did have, was options. Options are something that has been taken away over the years through weird UX choices.

psunavy03 3y ago

You don't seem to understand the point of ABS brakes. The way to achieve maximum deceleration in a car IS to lock up the wheels. The reason ABS brakes exist is because when the wheels are locked, the car is sliding as opposed to rolling, which causes the car to skid instead of turn when you turn the steering wheel. Average drivers tend to struggle with this and end up spinning out of control. So ABS brakes pump the brakes rapidly as a compromise between controllability and stopping distance, which allows the average driver in an emergency to just "stomp and steer" instead of having to learn how to control a skid, which is a more advanced driving skill. But they do this at the expense of stopping distance, which is longer than if you just locked up the brakes. Putting the transmission in park was still unnecessary and probably useless. It's not designed for that force, so it didn't absorb any energy or help the car stop faster; it just blew up.

kqr 3y ago
I'm not sure this is true. Yes, steerability is the main benefit of ABS, but I think bringing wheels from a slight roll to skid absorbs more energy (through deformation of the rubber) then just skidding along would under the same time frame. I.e. ABS does marginally decrease stopping distance -- at least on asphalt -- compared to plain skidding friction.
rootusrootus 3y ago
> The way to achieve maximum deceleration in a car IS to lock up the wheels That isn't true. Dynamic friction for a tire is always less than static friction, as soon as the tires are sliding your stopping distance is going to get longer. A good driver used to be able to threshold brake better than a basic ABS setup, but that hasn't been true now for years. Modern ABS computers are quite advanced.
outworlder 3y ago
> The way to achieve maximum deceleration in a car IS to lock up the wheels. Very much untrue and it's a subject covered by school physics textbooks. The wheels may not lock up simultaneously(often don't) and that is the reason why ABS will monitor wheels individually. And, if you are doing that, might as well do it all the time, and that's traction control. ABS decreases stopping distance and increases controllability. It's a win win. These days you can't really do any better than ABS, "average" driver or not.