Out-braking the ABS myth [video] • Hacker News Board

Re: Out-braking the ABS myth [video]

#31

Post by thereisnospork » Mon, Nov 06, 2023, 4:59 PM UTC

rqtwteye wrote: post #21

j-a-a-p wrote: post #4

I did a anti-slip course where we learned dosed breaking to reduce break distance. And once a circuit racing course where the instructor just told me to break with all force available. The latter stuck. This instructor logic was, only if you are a pro driver you actually can outperform ABS. In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back c…

"In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back collisions. Once I pushed so hard the break light sensor had to be replaced." I think full braking should be part of driver training. A lot of people I know are very hesitant to brake full force and I think a lot of accidents happen because people don't really brake all out when needed. As f…

>I think full braking should be part of driver training. A lot of people I know are very hesitant to brake full force and I think a lot of accidents happen because people don't really brake all out when needed.

Couldn't agree more. It's beyond negligent that with the current state of drivers ed the first time a driver will need to emergency brake, or even feel abs activate will be in a potentially life or deal situation.

Re: Out-braking the ABS myth [video]

#32

Post by lbussell » Mon, Nov 06, 2023, 5:01 PM UTC

I ride motorcycles on the track, and most track riders/racers disable or delete ABS on their bikes. The idea of ABS sounds great, but it’s often too primitive for high performance riding. On a hot summer day with sticky tires and a clean track, you’ll flip over the handlebars before you lock the front wheel. However, most ABS systems work by detecting the speed difference between the front and rear wheels. As you brake hard into a corner, the weight transfers forwards and the rear wheel can come completely off the ground. I’m braking as hard as possible but at this point the ABS sees the rear wheel spinning freely in the air and decides I don’t have brakes anymore. Check out this clip from WSBK for an extreme example of what I’m talking about: https://youtu.be/48lcS3hPVrE?si=UORAFvQt4Djf95Uv

I don’t claim to be able to out brake ABS on the varied conditions of the street though. I would NEVER turn off ABS outside a controlled environment. Honestly it should be a legal requirement for bikes just like cars and it’s pretty silly that manufacturers like to charge $500-1000 extra for this feature.

Re: Out-braking the ABS myth [video]

#33

Post by cf100clunk » Mon, Nov 06, 2023, 5:02 PM UTC

JohnBooty wrote: post #13

j-a-a-p wrote: post #4

I did a anti-slip course where we learned dosed breaking to reduce break distance. And once a circuit racing course where the instructor just told me to break with all force available. The latter stuck. This instructor logic was, only if you are a pro driver you actually can outperform ABS. In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back c…

I got really good at pumping the brakes (is that "dosed braking"? new term to me) in the days before ABS. You can definitely get close to the performance of ABS with practice. Used to practice in the snow, in empty parking lots. (ABS or no ABS, everybody should safely practice recovering from spins and slides in empty parking lots! It's also really fun...) The idea that a pro could outperform ABS is surprising to hea…

Prior to commonplace ABS in cars, pumping the brakes when traction was bad was a commonplace braking technique taught across Canada for winter driving. An added benefit was that the sudden, irregular flashes of brake lights ahead hopefully gave a good amount of warning to following drivers to let off their own gas pedal and do the same kind of brake pumping.

Re: Out-braking the ABS myth [video]

#34

Post by mindslight » Mon, Nov 06, 2023, 5:06 PM UTC

Is the default behavior in motorcycle land really to just use the back brakes? When I rode a bicycle in a city I learned to use both, but primarily my fronts. I definitely had some panic stops where I was modulating to prevent the rear wheel coming off the ground. But maybe the calculus changes with motorcycles' higher speed, as maintaining steerability becomes that much more important?

I'm actually kind of surprised a motorcycle ABS controller apparently doesn't include include sensors for the deceleration vector, bike rotation, the compression of the front shock, the weight on the rear wheel, etc. I'd think that a computer could reliably beat a human, given the right sensors.

Re: Out-braking the ABS myth [video]

#35

Post by tass » Mon, Nov 06, 2023, 5:06 PM UTC

iokanuon wrote: post #23

tass wrote: post #19

Earlier quoted context omitted.

In a modern ( In the past, this was likely true when ABS systems weren't able to control individual wheels. They can do that today, can check for wheel lock-ups and react dozens of times a second, and can therefore compensate for changing grip at different parts of the road during the entire stopping process. In formula 1, where ABS has been banned, drivers have the capability to manually adjust brake balance (front/…

This video is about motorcycles, not cars. Also, the data on this is in the linked video - the author demonstrates you can do a controlled stoppie to decelerate faster without ABS, because that's its main feature - preventing you from flying off the bike.

I've seen the video, but the comment I'm replying to seems to be referring to a car driving course.

I'm a little surprised there's no "pro ABS" for motorcycles which allows you to do a stoppie if you enable an option, and/or are keeping the bike perfectly straight.

Re: Out-braking the ABS myth [video]

#36

Post by j-a-a-p » Mon, Nov 06, 2023, 5:13 PM UTC

97-109-107 wrote: post #15

j-a-a-p wrote: post #4

I did a anti-slip course where we learned dosed breaking to reduce break distance. And once a circuit racing course where the instructor just told me to break with all force available. The latter stuck. This instructor logic was, only if you are a pro driver you actually can outperform ABS. In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back c…

I found a lot of humor in your anecdote that the light sensor had to be replaced. In a similar vein, a family member had a hardware issue in their laptop where some keys would not register some of the time (moisture). Their understanding was that they did not press hard enough for the device to register the press. This confusion between the boundaries of electronic and mechanical problems led to some mocking. If your…

I can dig deeper behind my face. It was a Volvo 850. After the incident the brake lights kept on. I had to repair the car twice. The first responding mechanic had a single sensor that sort of fitted. A few days later I had my regular mechanic replace it with the stock double sensor. IIRC this model has one sensor for the brake lights and one for the cruise control.

Re: Out-braking the ABS myth [video]

#37

Post by grecy » Mon, Nov 06, 2023, 5:14 PM UTC

rqtwteye wrote: post #21

j-a-a-p wrote: post #4

I did a anti-slip course where we learned dosed breaking to reduce break distance. And once a circuit racing course where the instructor just told me to break with all force available. The latter stuck. This instructor logic was, only if you are a pro driver you actually can outperform ABS. In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back c…

"In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back collisions. Once I pushed so hard the break light sensor had to be replaced." I think full braking should be part of driver training. A lot of people I know are very hesitant to brake full force and I think a lot of accidents happen because people don't really brake all out when needed. As f…

> I think full braking should be part of driver training

I thought it was. I distinctly remember my Dad telling me to slam on the brakes while teaching me to drive. I pushed them hard, but nothing crazy. He said to get up to speed and kick the pedal through the floor and hold it there.

Older car, full lockup and skid for a good distance. We did that more than once.

Now 25 years later, I do exactly the same thing every year at the first snowfall , and a few times during the winter to get the feel of everything going extremely vague.

Re: Out-braking the ABS myth [video]

#38

Post by dsego » Mon, Nov 06, 2023, 5:16 PM UTC

rqtwteye wrote: post #21

j-a-a-p wrote: post #4

I did a anti-slip course where we learned dosed breaking to reduce break distance. And once a circuit racing course where the instructor just told me to break with all force available. The latter stuck. This instructor logic was, only if you are a pro driver you actually can outperform ABS. In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back c…

"In emergency situations I break with full force without hesitation. This has lead to multiple avoided crashes and TBH two back collisions. Once I pushed so hard the break light sensor had to be replaced." I think full braking should be part of driver training. A lot of people I know are very hesitant to brake full force and I think a lot of accidents happen because people don't really brake all out when needed. As f…

But it also requires some resolve when the abs starts pushing back on the pedal. The instinct is to lift your foot instead of fighting the pedal, which is what you should do.

Re: Out-braking the ABS myth [video]

#39

Post by cwillu » Mon, Nov 06, 2023, 5:16 PM UTC

david_acm wrote: post #29

JohnBooty wrote: post #13

Earlier quoted context omitted.

I got really good at pumping the brakes (is that "dosed braking"? new term to me) in the days before ABS. You can definitely get close to the performance of ABS with practice. Used to practice in the snow, in empty parking lots. (ABS or no ABS, everybody should safely practice recovering from spins and slides in empty parking lots! It's also really fun...) The idea that a pro could outperform ABS is surprising to hea…

I believe the term "pumping the brakes" refers to applying and releasing pressure on the brakes. With ABS off, a tire that's locked up (not spinning) will stop in a significantly longer distance than one that's at the limit of grip (slipping with a slight under-rotation). Assuming you have exceeded the limit of grip of the tires with the initial brake bite and the tires have started to lock up, by releasing and reapp…

Amusingly, a loadcell is in fact a very precise measurement of how far something has travelled in response to a load. More specifically, a resistor changes value very slightly as it is compressed or expanded. If you laminate a resistor to a strip of metal, you can use that change in resistance to measure the deflection, and then derive the force that drove that deflection. In principal you can get the same information with a lever attached to the same strip connected to a potentiometer; indeed, lever scales based on amplifying the deflection like that used to be universally used.

Source: I was a loadcell technician in a previous life.

Re: Out-braking the ABS myth [video]

#40

Post by Swizec » Mon, Nov 06, 2023, 5:16 PM UTC

tomtheelder wrote: post #22

Swizec wrote: post #9

FortNine is great but the conclusion in this video is a little silly. The best result comes from threshold braking with ABS enabled. Yeah no shit. As described in the video, motorcycles perform funny under braking. If you slam the brakes too fast, you have very little grip. ABS kicks in and you’re not stopping. If you progressively brake correctly, you transfer load to the front tyre and increase grip. ABS kicks in,…

I'm confused by which part of the conclusion you thought was silly. It seems like you reached the exact same conclusion than the video did, and I don't think it's at all obvious to most people that you are still supposed to threshold brake with ABS.

The silly/unfortunate part is that most people can’t threshold brake in emergency situations.

It’s like saying “Doing the perfect thing every time is best”. Which is true but not useful.

And they teach you about progressive braking in the first hour of learning to ride. Then they keep repeating it all the time. Every rider on the road knows that they should do this. It’s the execution that is hard.