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This is why ABS haters are wrong

WWWobble said:
...nowhere in this debate is there enough discussion about how to avoid instances that require "threshold braking" ON THE STREET in the first place...
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Yes, it's amazing how as you get more experienced the need for panic braking diminishes. I have only one bike with ABS, I tested it on the way home from the dealer, that was the last time it activated.
 
aciurczak said:
All motorcycle systems (and all car systems for 20 years at this point) monitor each wheel independently. You're going to have to expand on this particular brand of "logic".
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No, I mean independent in the sense of independent systems for each wheel that don't communicate with each other.
 
ilikefood said:
No, I mean independent in the sense of independent systems for each wheel that don't communicate with each other.
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Here's what you posted:

ilikefood said:
Even worse, some motorcycle ABS monitors wheels independently, and then it's a total guess as to when the tire is about to start slipping.
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How does having independent systems, that are individually monitoring wheelspeed rate changes, translate into it being a total guess as to when the tire is about to start slipping?
 
aciurczak said:
Here's what you posted:



How does having independent systems, that are individually monitoring wheelspeed rate changes, translate into it being a total guess as to when the tire is about to start slipping?
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If the systems are independent (meaning they don't talk to each other), then the ABS isn't comparing wheel speeds. If it isn't comparing wheel speeds, it doesn't know what the slip rate of the front wheel is, and has to guess when the front wheel will lock, based on hard-coded parameters, like the maximum deceleration rate the system thinks is possible.

Even with integrated ABS that can compare front and rear wheel speeds, figuring out when the front tire is about to start sliding is difficult. It's an easy problem in a car because you have 4 wheels that remain in contact with the ground. On a motorcycle under hard braking the rear wheel will barely contact the ground, so ABS can't rely on the rear wheel speed as an input.
 
Burning1 said:
The review you're referring to makes it clear it's an issue specific to the Multistrada. BMW has had some issues with their ABS systems as well.
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Right. Which is why I'm saying that there is a big difference between how well different AB systems work, and that some of them are really shitty.

I don't need you to explain ABS systems to me. This whole conversation has been done to death. Your argument is re-treading a lot of old ground.
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Well, you seem to think that ABS wouldn't release brakes before an experienced rider would in the same situation, which tells me that you don't really understand how ABS works.
 
louemc said:
That's a crucial/key point...

And for the life of me, I can't put into words, what I'm doing with my mind (at least all of the process),in avoiding the getting to the need of braking "threshold"....Or even how to sense, just what the tire is doing, while approaching that edge.

Aggressively riding rocky, rutted, muddy, steep, mountain trails.. taught the control....
Decades of riding street, taught the dealing with other vehicles.
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Dude, you've never ridden an ABS bike.

Can it.
 
ilikefood said:
If the systems are independent (meaning they don't talk to each other), then the ABS isn't comparing wheel speeds. If it isn't comparing wheel speeds, it doesn't know what the slip rate of the front wheel is, and has to guess when the front wheel will lock, based on hard-coded parameters, like the maximum deceleration rate the system thinks is possible.
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You're stuck in a loop. There isn't guessing involved. There are physical limits to how fast a wheel can be decelerated without slipping more than appropriate. That is being directly measured, and acted upon when the rate exceeds the chosen parameters. You continue to make false assumptions that the rate is chosen well before any slip would occur.

ilikefood said:
Even with integrated ABS that can compare front and rear wheel speeds, figuring out when the front tire is about to start sliding is difficult. It's an easy problem in a car because you have 4 wheels that remain in contact with the ground. On a motorcycle under hard braking the rear wheel will barely contact the ground, so ABS can't rely on the rear wheel speed as an input.
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While the other wheel speed can be taken into account, it's still just one of the parameters. Cars can (and need to be able to) brake individual wheels based on the conditions being faced by that particular wheel, independent of the wheel speeds of the other 3. The ABS continues to calculate slip rate per tire, independently, to make those decisions. (one side of the car on a strip of ice, the other not, as the easiest example).
 
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aciurczak said:
You're stuck in a loop. There isn't guessing involved. There are physical limits to how fast a wheel can be decelerated without slipping more than appropriate. That is being directly measured, and acted upon when the rate exceeds the chosen parameters. You continue to make false assumptions that the rate is chosen well before any slip would occur.
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First of all, read up on tire slip rates and how they relate to ABS function. You get maximum braking force when the tire slip rate is somewhere around 20%, meaning the tire is rotating 20% slower than its forward motion. ABS works best when it can calculate the tire's slip rate and keep it around 20%.

The limit to how fast a wheel can be decelerated without slipping varies depending on the surface. ABS has a parameter that specifies the MAXIMUM deceleration rate it thinks a tire can handle. ABS isn't magic, it doesn't know the actual deceleration rate that's possible at any given moment.

The only thing that is "being directly measured" is wheel speed. ABS knows the following things:

1. The maximum possible deceleration rate. This is the rate hard-coded in the system when it leaves the factory.

2. The deceleration rate of the front wheel.

3. Speed of the rear wheel

If the rear wheel stays on the ground, the ABS can calculate the front tire's slip rate, and keep it around 20%. This works in low-traction conditions. Under hard braking, the rear tire's speed reading isn't reliable, so the only thing the ABS can rely on is the deceleration rate of the front wheel. If the deceleration rate exceeds the hard-coded maximum, the ABS activates. This is what I mean about "taking a guess" about when the tire will start sliding. Depending on actual conditions, ABS can trigger too early or too late.

While the other wheel speed can be taken into account, it's still just one of the parameters. Cars can (and need to be able to) brake individual wheels based on the conditions being faced by that particular wheel, independent of the wheel speeds of the other 3. The ABS continues to calculate slip rate per tire, independently, to make those decisions. (one side of the car on a strip of ice, the other not, as the easiest example).
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Right. I'm not saying anything different. I think you misunderstood how I used the word "independent".
 
That assumes that a bike can decelerate at that rate without pulling a stoppie. If the bike stoppies at a rate of deceleration that occurs when you have only 5% tire slip, the ABS will only engage when you have done something to force it to engage - grabbing the brakes, compromised traction, etc.

That makes your concerns completely irrelevant, unless you are in a situation of compromised traction, where we already agree ABS modulates the brakes more effectively than a human can.

This also matches well with my experiences of tracking a bike with ABS - it didn't engage the ABS until either the bike began to stoppie (at which point it managed it before it got more than 1-2 inches off the ground), despite controlled sliding of the rear wheel. The ABS at no point engaged under normal usage of braking until the bike began to stoppie, on OEM tires.

Note that this was setting it on front engagement only. It would cycle the ABS in "front and rear mode" if you locked or began to slide the rear wheel on the brakes due to aggressive downshifting, but that is to be expected as you are intentionally mis-matching the tire speeds at that point in such a fashion that does interfere with normal ABS operation.
 
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Emergency braking is not threshold braking; those are different skills.

Threshold braking is a bullshit skill. It's only useful on bike big enough to keep the rear end down, on ideal surfaces. It's a masturbatory technique; one that will not improve safety in the slightest.

There has literally never been a situation where I've said "man, if only I had practiced my threshold braking." I've literally never met someone who has said that. The closest I've come was a crash in the rain. We've already established that ABS is the superior condition in that situation.
 
GAJ said:
Dude, you've never ridden an ABS bike.

Can it.
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:rofl Since You don't do much on a bike, you can't comprehend.

I don't have the need, for more help. I like dealing with what comes up, with the package I carry, it delivers.
 
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ilikefood said:
The only thing that is "being directly measured" is wheel speed. ABS knows the following things:

1. The maximum possible deceleration rate. This is the rate hard-coded in the system when it leaves the factory.

2. The deceleration rate of the front wheel.

3. Speed of the rear wheel
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The rate of deceleration and speed are monitored on both wheels. You also forgot accelerometer(s) and gyros (on some).
 
russ69 said:
Yes, it's amazing how as you get more experienced the need for panic braking diminishes. I have only one bike with ABS, I tested it on the way home from the dealer, that was the last time it activated.
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I likewise have only used ABS during testing except for 2 times other than dirt slope freewheeling. Both in foreign countries on rental bikes. Both times it saves a crash.
 
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