This is why ABS haters are wrong

[GAJ]

I guess he's not wrong, actually...

He's never ridden a bike with it to my knowledge.

So GIGO.

 

[Hooli]

This subject is bring hilarious, out of the woodwork.

Sigline material right here folks.

 

[ilikefood]

Because the goal isn't "stop the bike as quickly as possible" the goal is "use the ABS while stopping and see how that affects braking distance". You can't test ABS without engaging the ABS, engaging the ABS requires locking one wheel or another...

That's some crazy mental gymnastics again. The goal of the test is to determine how much distance a bike requires to stop from 60 mph. That's it. Brake as hard as you can, first with ABS and then without. It's really not that complicated. MCN has tested multiple motorcycles with and without ABS, and some AB systems do much better than Multistrada's. Here is a list of stopping distances compiled from MCN. Triumph Tiger's ABS extends stopping distance only by 6 feet. Multistrada's ABS extends it by 44 feet. The problem is without a doubt with the Multistrada's ABS, and not with the testing.

And situationally, there is a time to release the front brake when the rear locks - when you've unloaded the rear to the point that it locks when the rear wheel lifts - releasing the front keeps the rear wheel in contacts with the ground and allows for steering inputs.

Right. And when you're braking yourself, you can tell if the rear wheel is locked because it has lifted, or because you stepped on the rear brake too hard. A bad AB system won't know this, it will release the front brake, and extend your braking distance.

And I'm saying that this is inherently, completely, 100% wrong when it comes to modern ABS bikes. You are making assumptions about a feature on a bike you don't own, and I own one, have used it on the track, used it on the street, and am telling you that what you are concerned about simply doesn't happen anywhere but under the rarefied physics of an internet argument. You can easily reach the limits of braking force on clean, good pavement without ever triggering the ABS.

If what you're saying were true, there would be NO DIFFERENCE in braking distances on clean, dry pavement between ABS and non-ABS bikes. But there are differences, which means that ABS does indeed get triggered on clean, dry pavement, extending stopping distances. I'm sorry, but facts are in direct opposition to your opinion.

 

[Marcoose]

This thing about stopping quicker w/o ABS in clean and dry pavement, is it in real panic situations or in mock emergency stops?

 

[ilikefood]

This thing about stopping quicker w/o ABS in clean and dry pavement, is it in real panic situations or in mock emergency stops?

Mock emergency stops. My whole point is that you can't learn how to threshold brake on an ABS bike. I'm not opposed to good ABS in general, as long as it can be turned off.

 

[NoobCorpse]

Just because you never braked hard enough to trigger ABS when braking on clean, dry pavement, it doesn't mean that it's impossible to do so. The proof is in the fact that good riders outperform ABS on clean, dry pavement. In the case of the Multistrada ABS, they outperform by 44 ft from 60 mph. This wouldn't be the case if the ABS didn't trigger.

Dude. I'm not saying it's impossible to do so, at all. I'm saying I have extensive experience braking HARD on pavement, and have done it without engaging ABS. I have engaged ABS, but the circumstances where it engaged, it was very obvious why it engaged.

Again, this is under normal street riding conditions (spirited pace, traffic, parking lots, etc), so I'm not doing brake testing or trackdays or going out of my way to trigger it. So, in my experience, I have not seen ABS intrude or engage prematurely in my everyday riding. And again, the times it has, it's been obvious as to why it engaged (slippery road surface, rough pavement, etc) and it has not been a negative experience when it has.

 

[redtail]

My whole point is that you can't learn how to threshold brake on an ABS bike.

You've been stating this as though its a known fact, please provide a source.

 

[Marcoose]

Mock emergency stops.

Anyone that has seen its whole life go by in a blink of an eye knows there's a monumental physiological difference btw real and mock emergency, even after 100 practices. In a real emergency, my money is on the cold-blooded technology, easily 9 out of 10 times. That 1 time is just dumb luck.

 

[Z3n]

That's some crazy mental gymnastics again. The goal of the test is to determine how much distance a bike requires to stop from 60 mph. That's it. Brake as hard as you can, first with ABS and then without. It's really not that complicated. MCN has tested multiple motorcycles with and without ABS, and some AB systems do much better than Multistrada's. Here is a list of stopping distances compiled from MCN. Triumph Tiger's ABS extends stopping distance only by 6 feet. Multistrada's ABS extends it by 44 feet. The problem is without a doubt with the Multistrada's ABS, and not with the testing.



Right. And when you're braking yourself, you can tell if the rear wheel is locked because it has lifted, or because you stepped on the rear brake too hard. A bad AB system won't know this, it will release the front brake, and extend your braking distance.



If what you're saying were true, there would be NO DIFFERENCE in braking distances on clean, dry pavement between ABS and non-ABS bikes. But there are differences, which means that ABS does indeed get triggered on clean, dry pavement, extending stopping distances. I'm sorry, but facts are in direct opposition to your opinion.

That link is 2 years old, for one, with bikes even older than that in the list. So the first thing is that yes, ABS tech is still advancing, as evidenced by the MSC system.

Second, I doubt their testing methodology because I have ridden a multistrada from that generation with the ABS enabled, i have friends who track their multis with ABS engaged (racers and trackday instructors included in those groups), and it is very rare to have the ABS engage, even when hard braking over bumps, coming hard into corners on the track, etc.

Some posters in this thread claim they are constantly cycling the ABS as they come to a stop, and to me that indicates there is a flaw in their braking technique that's causing the wheels to lock under circumstances in which they shouldn't lock. Similarly, I wonder if the MCN rider is doing something that is causing early or excessive engagement of the ABS system, as I nearly never experience ABS engagement.

ABS systems and implementations do vary in their execution, and understanding how they do is essential to getting the most out of bike, just like you'll need to use more rear brake to get ideal stopping distance on a bike that isn't wheelbase limited, like a cruiser.

None of that indicates that ABS systems stop threshold braking practice - it just indicates that even with rider aids, someone will find a way to make it perform poorly - the difference is that you won't crash while using ABS equipped brakes poorly, but you sure as hell will if you do the same without ABS.

 

[ilikefood]

You've been stating this as though its a known fact, please provide a source.

It's really simple:

1. Stopping distances on ABS-equipped bikes are longer than on non-ABS bikes on clean, dry pavement. Even on the same bikes. This is a fact.

2. This means that ABS is triggered and reduces braking force before a good rider would reduce the braking force.

3. This means that you won't be able to maintain as much braking force as is required for threshold braking on an ABS bike, because the ABS will intervene and reduce the braking force for you.

Now, what part of this logic do you disagree with?

 

[ilikefood]

Anyone that has seen its whole life go by in a blink of an eye knows there's a monumental physiological difference btw real and mock emergency, even after 100 practices. In a real emergency, my money is on the cold-blooded technology, easily 9 out of 10 times. That 1 time is just dumb luck.

Yes, I agree with this.

 

[MCSFTGUY]

Your understanding of how tires work is way too simplistic. Static and kinetic friction is a convenient simplification used in high school physics classes, but reality is a lot more complicated.

As I keep saying, the transition from static friction to kinetic friction for a tire rolling on asphalt is GRADUAL, not sudden. It happens over a continuum. If you gradually increase brake pressure, the tire will at first roll at a speed that matches the speed of the forward motion of the bike. Then the tire will start partly sliding and partly rolling, so its rolling speed will be somewhat slower than the forward motion of the bike. As you continue increasing brake pressure, the difference between the tire's rolling speed and the forward speed of the bike will increase, and at some point the tire will lock (stop rolling entirely) and start sliding.

This is NOT a simple sudden transition from static friction to kinetic friction! The accelerometer test you saw merely captured the drop in braking force when the tire locked up completely, but the tire was partially sliding way before then.

OK.... I can agree with you that it is not a sudden transition... but you need to define what your time frame is for a suddent transition.

And the I will agree with you when you talk about there being a slight difference in rotational tire speed verse forward speed of the motorcycle that the tire will not necessarily lock up. In the crash business this is known as impending skid.... and it leaves a very distinctive mark on the roadway.

I will also go so far as to say that a highly skilled rider can feel the preformance change of the motorcycle and realize when the brake force at the rotors is just right to match the minor flex of the contact patch....

I will submit that less than 1% of the riders out there have the technical skill. Present company of BARFers accepted.

As for the accelerometer trace.... Vericom 5000 with a sampling rate at 100Hz. The lock up occurred within 10 milli-seconds....

This time frame is way out side of what any person can respond to.....

As for "Static and kinetic friction is a convenient simplification used in high school physics classes"

I guess the time I spend in college taking physics mechanics classes as well as the post grad classes in mechanics and mathematical physics I took were overrated.

 

[redtail]

AMA mythbusters: http://www.americanmotorcyclist.com/Features/RideReports/AntiLockBraking.aspx

 

[MCSFTGUY]

Mock emergency stops. My whole point is that you can't learn how to threshold brake on an ABS bike. I'm not opposed to good ABS in general, as long as it can be turned off.

I have to disagree with this... in fact I would go so far to say that the safest way to learn threshold braking is by using an ABS equiped motorcycle because if you go to far you won't lock up and run the risk of crashing.....

My disagreement comes from the following... as far as I know the MCN testers use an ABS equiped motorcycle to test both the threshold braking and ABS system.... If you can maintain threshold braking the ABS will not kick in.

The whole theory behind ABS is to keep the motorcycle in threshold braking for as long as possible. As I said in a previous post, when threshold braking moves into lockup, the ABS computer senses the lack of wheel speed, reduces the fluid pressure in the braking system to allow the wheel to roll again... not free wheel there is still braking involved, the pressure builts back up to the point of lock up again and then the pressure is released to allow wheel roll and builts back up again.... this is the whole idea of the pulse felt in the brake handle and foot pedal... the lock release cycle... It is because of the release cycle that the a highly skilled rider can stop better than a rider

The easiest way to feel this pulse is in your car since most cars have ABS now.... on a clear roadway with nobody behind you drive about 40 mph and stomp on the brake pedal as hard as you can.... you will feel the pulsing in the pedal.....

 

[ilikefood]

OK.... I can agree with you that it is not a sudden transition... but you need to define what your time frame is for a suddent transition.

It's not a question of time, but of braking force. The tire can stay in that partly sliding, partly rolling state until it stops if the braking force is constant. What causes the transition to 100% sliding is an increase in the braking force.

I will also go so far as to say that a highly skilled rider can feel the preformance change of the motorcycle and realize when the brake force at the rotors is just right to match the minor flex of the contact patch....

I will submit that less than 1% of the riders out there have the technical skill. Present company of BARFers accepted.

Sure. And the point of practicing threshold braking is to learn how to feel when the tire is in that in-between sliding/rolling state. I'm talking about learning how to brake better. I'm not disputing the usefulness of good ABS in regular riding, when you're not practicing braking.

As for the accelerometer trace.... Vericom 5000 with a sampling rate at 100Hz. The lock up occurred within 10 milli-seconds....

This time frame is way out side of what any person can respond to.....

Within 10 ms of what? Again, the transition to 100% locked up happens when the braking force exceeds the tire's limits. It has nothing to do with time. If you increase the braking force faster, the transition to sliding will happen faster.

 

[Z3n]

Oh, another key point about braking with ABS - each system has it's own "system" of release. The KTM goes "fuzzy" on the front lever, but kicks the rear brake back at you. That "fuzzy" allows you to dial in the amount of braking you want when the ABS is done sorting things out. If you release the brake when it does that, you will massively extend your braking distance. On the BMWs R1200s I've cycled the ABS on, the front brake kicks and you have to hold tightly or it will increase braking distance. The S1000RR doesn't do that.

Again, technique and a familiarity with what the system does counts when you're trying to get 1/10ths out of a bike, ABS or no.

 

[MCSFTGUY]

Within 10 ms of what? Again, the transition to 100% locked up happens when the braking force exceeds the tire's limits. It has nothing to do with time. If you increase the braking force faster, the transition to sliding will happen faster.

My Bad.... when the amount of pressure applied to the braking system throught the handle and foot pedal resulted in too much braking force at the rotors on the wheels, the transition from static friction to kinetic friction occurred within 10 milli-seconds.

And to me, you can't ignore time because impulse (imp = Ft) and friction is a force that comes in two flavors and since the braking force is a changing force it can be viewed as an impulse.

And, by definition, time and distance are the two basic quantities of motion... and we are in fact talking about the motion of an object.

 

[aciurczak]

It's really simple:

1. Stopping distances on ABS-equipped bikes are longer than on non-ABS bikes on clean, dry pavement. Even on the same bikes. This is a fact.

Have to be careful with the absolutes. MCN just tested the Hondas CB1100 this month, and the ABS version stopped 20 feet shorter than the non ABS on dry pavement. The differences on other bikes have been coming down sooner than you're giving credit for.

2. This means that ABS is triggered and reduce braking force before a good rider would reduce the braking force.

No, that's your interpretation. It could just as easily be the fact that ABS bikes provide worse feel at the lever, making it harder to judge exactly when lockup would occur. It does not require that the ABS is triggered and reducing braking force. If that equally possible factor is in play, it stands to reason that better ABS systems that continue to provide proper braking feel would continue to slice that gap, even if it were significant a few years back.

3. This means that you won't be able to maintain as much braking force as is required for threshold braking on an ABS bike, because the ABS will intervene and reduce the braking force for you.

No, see above.

Now, what part of this logic do you disagree with?

Some (but not all) of yours. You are taking your biases and trying to make the data fit them, rather than the other way around.

 

[bikeama]

We don't need all this fancy stuff! What we have works

Points and condensers can be fixed by any rider and the ticklers always work once mastered.*

*sarcasm

 

[mrmarklin]

Like Lou, I've been riding all my adult life, and of course ride to perfection.

Even so, having had ABS on my vehicles the last 20 years, I can't wait to get it on my next motorcycle.