ABS Brakes
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Tourer
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From: Cornwall, Ontario, Canada
ABS Brakes
For those of you that think you can brake more effectively without ABS, you may want to read this:
James R. Davis
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[HIGH Karma] Houston, TX
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Posted - * Today * : 11:14 AM Excellent commentary but there is one aspect of your post that is quite wrong.
That is a declarative that is not supported by facts. Though it is a logical and reasonable conclusion based on how you framed it, here are the actual facts.
[Many of you will recall that when ABS was first made generally available on some motorcycles I was fundamentally against it. That, because it was a significant cost and based on the technology at the time, nowhere near as effective as contemporary designs now provide. Since then the costs have come down and, more importantly, the actuators and computer technology has VASTLY improved in terms of off/on speed. I am today a strong advocate of ABS, generally.]
Let's say that your tires and the roadway conspire to provide you traction until you reach a deceleration rate of 1.1g's. As you approach 1.1g's there will be a greater and greater amount of 'slip' as a greater portion of the contact patch is losing a firm grip on the roadway. At 1.1g's there will be nothing but 'slip' and the tire QUICKLY transitions from having the characteristics of the 'static coefficient of friction' to that of the 'dynamic coefficient of friction' - felt as a loss of traction of around 25-30%.
When the deceleration rate is somewhere in the high 0.9's the amount of 'slip' is noticed by the ABS system and braking force is diminished. IMMEDIATELY thereafter, when the amount of 'slip' has reduced, the braking pressure is reapplied. As a result, you maintain a deceleration rate in the high 0.9g's with ABS.
That is better deceleration than any but a TINY percentage of motorcyclists can achieve without ABS!!! The vast majority of motorcyclists DO NOT ALLOW THEMSELVES to achieve a deceleration rate in excess of 0.90g's - typically more like 0.8g's.
Thus, in a pristine environment where maximum braking is attempted, ABS wins virtually every time.
Then there is the case of suddenly reduced traction caused by road surface anomalies. In a hard braking effort the ABS equipped bike responds far more quickly than does even the most skilled rider, and a loss of traction is avoided by the ABS equipped bike while the non-ABS bike will more than likely begin a skid before the biker reacts properly (assuming he even does.) In any event, that ABS equipped bike stops more quickly than does the non-ABS equipped bike.
For the RARE instance where the rider's reactions and skill levels are well enough developed that the rider is able to deliberately brake at threshold levels, that biker CAN stop more quickly than can the ABS-equipped bike. But to declare that "a stop in which ABS comes on will be LONGER than one where you don't lock the wheel" suggests that this is always true and as I just demonstrated, it is not.
THERE IS ABSOLUTELY NO ARGUMENT that in the case of a rider who has 'panic' applied his brakes and locked them up as a result, the ABS-equipped bike will stop more quickly than will the non-ABS equipped bike. This is the fundamental advantage of ABS!!!!! The two 'controlled' scenarios I discussed above are icing on the cake.
For those of you who noticed that I included TECHNIQUE as well as reaction times in the comparisons, you should know that because human reaction times are so much slower than those of the ABS system, NO MATTER WHICH BRAKE IS LOCKED ON A NON-ABS EQUIPPED BRAKE, YOU MUST RELEASE THE FRONT BRAKE LEVER AS PART OF YOUR RECOVERY EFFORT - a technique that must be learned as it is not instinctive.
Patriot Guard Rider
It is written by James R Davis in response to comments on his motorcycle forum which can be found at:
http://www.msgroup.org/forums/mtt/default.asp
James R. Davis
Administrator
13087 Posts
[HIGH Karma] Houston, TX
USA
Honda
GoldWing 1500
Peer Review: 1 Peer Review Options
Posted - * Today * : 11:14 AM Excellent commentary but there is one aspect of your post that is quite wrong.
quote: It is also important to remember that a stop in which ABS comes on will be LONGER than one where you don't lock the wheel
That is a declarative that is not supported by facts. Though it is a logical and reasonable conclusion based on how you framed it, here are the actual facts.
[Many of you will recall that when ABS was first made generally available on some motorcycles I was fundamentally against it. That, because it was a significant cost and based on the technology at the time, nowhere near as effective as contemporary designs now provide. Since then the costs have come down and, more importantly, the actuators and computer technology has VASTLY improved in terms of off/on speed. I am today a strong advocate of ABS, generally.]
Let's say that your tires and the roadway conspire to provide you traction until you reach a deceleration rate of 1.1g's. As you approach 1.1g's there will be a greater and greater amount of 'slip' as a greater portion of the contact patch is losing a firm grip on the roadway. At 1.1g's there will be nothing but 'slip' and the tire QUICKLY transitions from having the characteristics of the 'static coefficient of friction' to that of the 'dynamic coefficient of friction' - felt as a loss of traction of around 25-30%.
When the deceleration rate is somewhere in the high 0.9's the amount of 'slip' is noticed by the ABS system and braking force is diminished. IMMEDIATELY thereafter, when the amount of 'slip' has reduced, the braking pressure is reapplied. As a result, you maintain a deceleration rate in the high 0.9g's with ABS.
That is better deceleration than any but a TINY percentage of motorcyclists can achieve without ABS!!! The vast majority of motorcyclists DO NOT ALLOW THEMSELVES to achieve a deceleration rate in excess of 0.90g's - typically more like 0.8g's.
Thus, in a pristine environment where maximum braking is attempted, ABS wins virtually every time.
Then there is the case of suddenly reduced traction caused by road surface anomalies. In a hard braking effort the ABS equipped bike responds far more quickly than does even the most skilled rider, and a loss of traction is avoided by the ABS equipped bike while the non-ABS bike will more than likely begin a skid before the biker reacts properly (assuming he even does.) In any event, that ABS equipped bike stops more quickly than does the non-ABS equipped bike.
For the RARE instance where the rider's reactions and skill levels are well enough developed that the rider is able to deliberately brake at threshold levels, that biker CAN stop more quickly than can the ABS-equipped bike. But to declare that "a stop in which ABS comes on will be LONGER than one where you don't lock the wheel" suggests that this is always true and as I just demonstrated, it is not.
THERE IS ABSOLUTELY NO ARGUMENT that in the case of a rider who has 'panic' applied his brakes and locked them up as a result, the ABS-equipped bike will stop more quickly than will the non-ABS equipped bike. This is the fundamental advantage of ABS!!!!! The two 'controlled' scenarios I discussed above are icing on the cake.
For those of you who noticed that I included TECHNIQUE as well as reaction times in the comparisons, you should know that because human reaction times are so much slower than those of the ABS system, NO MATTER WHICH BRAKE IS LOCKED ON A NON-ABS EQUIPPED BRAKE, YOU MUST RELEASE THE FRONT BRAKE LEVER AS PART OF YOUR RECOVERY EFFORT - a technique that must be learned as it is not instinctive.
Patriot Guard Rider
It is written by James R Davis in response to comments on his motorcycle forum which can be found at:
http://www.msgroup.org/forums/mtt/default.asp
Last edited by bob_kikkert; Oct 31, 2008 at 12:22 PM.
Advanced
Joined: May 2008
Posts: 65
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From: Iraq, South of Baghdad
Maybe this will finally get the ABS haters to stop...my money is that despite this well written and completely factual article, people will say that ABS is trash and they would rather have their bike old school and want to control the braking themselves.
Let the debate begin....again...again...etc.
Let the debate begin....again...again...etc.
Tourer
Joined: Apr 2008
Posts: 395
Likes: 0
From: San Berdo, So. Cal
I was never a fan of ABS having been through several emergency vehicle training programs that taught threshhold braking and other techniques.
This plus the experiences I had in a Chevy Astro van, came to a red light with my head up my butt and tried to brake, felt I had enough distance to do it as I had been taught, but the ABS pumped the whole time I was rolling through the intersection.
Luckily it was empty.
This last weekend while riding in a parking lot on my Ultra I was following a car out of the lot and thought he was going left, thats what his blinker said, and he turned right.
I was at slow speed and hit the brakes and the front brakes pumped as ABS do.
If it weren't for the slow speed and the ability to get my boot on the ground I would have dumped the bike.
When you get a bike with ABS Harley sends a DVD showing how it helps you stop properly.
I was impressed my the demonstration and was glad to have it.
Time will tell, hopefully I will not be writing about any near crash episodes.
This plus the experiences I had in a Chevy Astro van, came to a red light with my head up my butt and tried to brake, felt I had enough distance to do it as I had been taught, but the ABS pumped the whole time I was rolling through the intersection.
Luckily it was empty.
This last weekend while riding in a parking lot on my Ultra I was following a car out of the lot and thought he was going left, thats what his blinker said, and he turned right.
I was at slow speed and hit the brakes and the front brakes pumped as ABS do.
If it weren't for the slow speed and the ability to get my boot on the ground I would have dumped the bike.
When you get a bike with ABS Harley sends a DVD showing how it helps you stop properly.
I was impressed my the demonstration and was glad to have it.
Time will tell, hopefully I will not be writing about any near crash episodes.
Seasoned HDF Member
Joined: Oct 2007
Posts: 10,946
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From: Nevada
ABS saved my bacon one day. I was riding my BMW in the rain when a cage suddenly pulled out in front of me. I couldn't swerve left or right. ABS allowed me to make a controlled stop well short of the cage.
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From: Dry Ridge, Ky.
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I am in the process of deciding between a Softail (no ABS) and a touring line bike (RKC--which has the ABS option)... that ABS option is becoming a bigger and bigger factor in my ultimate decision. I have two kids at home... seems like anything I can do to increase safety is an obligation.
another interesting report: http://wtopnews.com/?nid=116&sid=1501687
regards,
Drew
BTW: In NO way am I implying that those who do not choose ABS do not care about their kids/families/pesonal well-being. This is just a factor that is shaping MY decision for my next ride.
another interesting report: http://wtopnews.com/?nid=116&sid=1501687
regards,
Drew
BTW: In NO way am I implying that those who do not choose ABS do not care about their kids/families/pesonal well-being. This is just a factor that is shaping MY decision for my next ride.
Last edited by Drew_72; Oct 31, 2008 at 03:44 PM.
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From: Texas
[QUOTE=bob_kikkert;4057847]For those of you that think you can brake more effectively without ABS, you may want to read this:
QUOTE]
I read an article prior to buying my last bike ('08 Ultra w. ABS) that was about braking with and without ABS. The did testing of each with 3 different bikes, none HD, and with 5 different experience level riders. The most experienced rider was a member of a competition racing team, and the least had 4000 total miles on a bike of any kind.
These tests had some wrinkles to simulate real world braking. For example on the straight-line dry payment stopping test, they placed a steel manhole cover right in the path so the riders had to account for a slippery spot during breaking. In this test, the more experience the rider had the shorter distance they could stop with or without ABS brakes. The ABS helped the least experienced to stop sooner, but it showed experience had a more dramatic effect on stopping ability.
However on wet pavement, it enabled the least experience rider to stop as fast as the most experienced rider.
Basically the determination was that ABS brake are worth thier costs regardless of experience level, but experience is still a huge factor is safe riding.
QUOTE]
I read an article prior to buying my last bike ('08 Ultra w. ABS) that was about braking with and without ABS. The did testing of each with 3 different bikes, none HD, and with 5 different experience level riders. The most experienced rider was a member of a competition racing team, and the least had 4000 total miles on a bike of any kind.
These tests had some wrinkles to simulate real world braking. For example on the straight-line dry payment stopping test, they placed a steel manhole cover right in the path so the riders had to account for a slippery spot during breaking. In this test, the more experience the rider had the shorter distance they could stop with or without ABS brakes. The ABS helped the least experienced to stop sooner, but it showed experience had a more dramatic effect on stopping ability.
However on wet pavement, it enabled the least experience rider to stop as fast as the most experienced rider.
Basically the determination was that ABS brake are worth thier costs regardless of experience level, but experience is still a huge factor is safe riding.
Club Member
Joined: Jun 2008
Posts: 17,717
Likes: 1
From: NY
Yes there have been posts on here where people swore they could stop better on a bike without ABS than a bike with ABS. Hard to believe but there are those that think it.