abs pros/cons
Cruiser
Joined: Aug 2008
Posts: 120
Likes: 0
I posted this some time ago, I'm re-posting as I think it's relevant here:
I've had a lot of experience with the HD ABS since it was introduced on the police motors in '05. Of course from '05 to "07 was the initial system, while the '08 and newer is the current system mated to the Brembo brakes.
The first thing to understand is how ABS works. Its sensors determine, through measurement of wheel speed when a lock-up is incipient. The system then begins modulating the brakes (releasing and re-applying them) at something like 6 or 7 times a second. This keeps something near the maximum braking, while allowing the wheels to keep rolling. There are two reasons a rolling tire is good. The first is the only one that matters for us on a motor - only a rolling tire can keep the motor upright. The second is that a skidding tire takes longer to stop. In a car both reasons are important, since ABS allows both a shorter stop than a skid, and allows the car to be steered.
Now a couple of more foundation points:
From the above you should realize ABS will not make you stop faster. In fact a perfect rider, under perfect conditions, can stop shorter without ABS, than with ABS. This is because ABS works by backing away slightly from maximum braking. The primary braking exercise in motor school is the Brake and Escape, that involves slowing from 40 MPH in less than 62 feet to a speed that allows maneuvering around a tight obstacle. When I started, ABS wasn't around yet. In every class we'd usually get one significant crash due to a locked front wheel the student did not handle properly (release immediately and properly re-apply). On top of that everyone was leaving a little of their braking power on the table, for fear of a lock-up. The point is these were very well trained riders, with perfect road conditions, reacting to a known hazard. Even then there were problems.
For training purposes, student officers are taught to brake without activating the ABS. If they do, it's not a successful run. Even an ABS equipped motor will stop shorter if the ABS is not activated.
In the Brake and Escape, if ABS is deliberately activated (through improper application of the brakes) and held throughout the exercise, it becomes very difficult to get the necessary slowing in the distance allowed.
So, what all the above is designed to point out is that ABS isn't the absolute fastest way to stop a motorcycle (or any vehicle). I suppose this is the point the guys who claim they don't want ABS are trying to make.
HOWEVER,
First, it's extremely unlikely that when you need maximum braking you will have perfect road conditions. Anything that changes the friction on your braking path it likely to cause a wheel lock. A pothole, a manhole, a painted line, sand, oil, or anything that is more slippery than the road surface will obviously cause an impending skid to become a locked-wheel skid.
Second, even if the road surface is perfect, are you willing to bet your life (or at least bet injury and property damage) that your braking skills are perfect? If your braking at the threshold, the only reason would be an emergency has arisen that you failed to foresee. I've practiced threshold braking probably in excess of 1000 repetitions, and yet have used the skill only once or twice on the road. Those times on the road I was fortunate enough to not lock a wheel. Practice and skill development is a big part of the reason why; good luck is another big part.
Finally, having ABS gives you the confidence to brake to the maximum. As I mentioned above, in the pre-ABS days, running the brake and escape exercise, I know I was always leaving a little of the motor's braking power on the table, for fear of locking a wheel. I was still successful, but not as confident as I could be. In my case this would manifest itself in uneven speed at the entry of the exercise. We're checked with radar, and 40 MPH is the correct speed to enter. A minimum of 38 MPH is required for a passing run. In the days before ABS my speeds would range from 38 up to about 43 MPH. Once I was able to take away the concern of locking a wheel, I was able to concentrate on dialing it in. My first exam on an ABS motor all four of my test runs were dead-on 40 MPH. My point is not simply to brag. Rather it's to illustrate that when you're braking to the threshold you have plenty to worry about. ABS allows you to concentrate on the important issues (evaluating the hazard, planning an escape route, downshifting to be in the proper gear should the hazard clear, etc) rather than simply concerning yourself with the mechanics of getting the maximum you can out of your brakes.
The technique of braking is exactly the same whether your motorcycle has ABS or not. The difference comes when the technique has failed. On a non-ABS motor it requires an immediate release and proper re-application, to handle a front wheel lock-up. That takes time, and time equals distance. It also takes a cool reaction to a hot situation. On an ABS motor, if the ABS activates, it IS an indication you've made a braking error. However, your response is simply keep pulling the lever, or pressing the pedal. As noted above, it will lengthen your braking distance, but by very little, and by far less than the method needed on a non-ABS motor. This means you can sit down later and consider how your braking error occurred, rather than letting the accident reconstructionist do it for you. (By the way if you have ABS, and you've felt it activate on the street, you should figure out what you're doing wrong in your braking, because you are doing something that can be improved).
So, the goal if you have ABS is to never know it's there. Just like all your other forms of insurance, and your other safety equipment. Unlike a helmet, a seat belt, an air bag, or car insurance, the beauty of ABS is it can jump in to prevent an accident, not just lessen the severity, or try to fix things later.
When you get the ABS motor, take it out to a parking lot and do some braking with it. Deliberately over-brake with the front and the rear, to activate the system in each. This way you'll know what it feels like, both in the lever/pedal, and how it makes the motorcycle behave (you'll feel the "brake-release-brake-release" as it modulates). The DVD that Harley provides with the ABS motors is well worth watching. It explains ABS, and it explains how the H-D system works and what you'll see and feel.
Finally, here are two videos:
Me on an ABS equipped motor (40 MPH entry speed):
And my friend David on a non-ABS motor (also 40 MPH entry):
It's the exact same exercise, run at the same speed. Hopefully you notice that the confidence imparted by the ABS allows me to run it a little more smoothly. However, the ABS system was not activated, and the motorcycle stops just as quickly as the non-ABS motor (in fact a little more quickly since the Brembos are a superior brake to the prior iteration).
Harris
Denver, CO
www.youtube.com/conedown
I've had a lot of experience with the HD ABS since it was introduced on the police motors in '05. Of course from '05 to "07 was the initial system, while the '08 and newer is the current system mated to the Brembo brakes.
The first thing to understand is how ABS works. Its sensors determine, through measurement of wheel speed when a lock-up is incipient. The system then begins modulating the brakes (releasing and re-applying them) at something like 6 or 7 times a second. This keeps something near the maximum braking, while allowing the wheels to keep rolling. There are two reasons a rolling tire is good. The first is the only one that matters for us on a motor - only a rolling tire can keep the motor upright. The second is that a skidding tire takes longer to stop. In a car both reasons are important, since ABS allows both a shorter stop than a skid, and allows the car to be steered.
Now a couple of more foundation points:
From the above you should realize ABS will not make you stop faster. In fact a perfect rider, under perfect conditions, can stop shorter without ABS, than with ABS. This is because ABS works by backing away slightly from maximum braking. The primary braking exercise in motor school is the Brake and Escape, that involves slowing from 40 MPH in less than 62 feet to a speed that allows maneuvering around a tight obstacle. When I started, ABS wasn't around yet. In every class we'd usually get one significant crash due to a locked front wheel the student did not handle properly (release immediately and properly re-apply). On top of that everyone was leaving a little of their braking power on the table, for fear of a lock-up. The point is these were very well trained riders, with perfect road conditions, reacting to a known hazard. Even then there were problems.
For training purposes, student officers are taught to brake without activating the ABS. If they do, it's not a successful run. Even an ABS equipped motor will stop shorter if the ABS is not activated.
In the Brake and Escape, if ABS is deliberately activated (through improper application of the brakes) and held throughout the exercise, it becomes very difficult to get the necessary slowing in the distance allowed.
So, what all the above is designed to point out is that ABS isn't the absolute fastest way to stop a motorcycle (or any vehicle). I suppose this is the point the guys who claim they don't want ABS are trying to make.
HOWEVER,
First, it's extremely unlikely that when you need maximum braking you will have perfect road conditions. Anything that changes the friction on your braking path it likely to cause a wheel lock. A pothole, a manhole, a painted line, sand, oil, or anything that is more slippery than the road surface will obviously cause an impending skid to become a locked-wheel skid.
Second, even if the road surface is perfect, are you willing to bet your life (or at least bet injury and property damage) that your braking skills are perfect? If your braking at the threshold, the only reason would be an emergency has arisen that you failed to foresee. I've practiced threshold braking probably in excess of 1000 repetitions, and yet have used the skill only once or twice on the road. Those times on the road I was fortunate enough to not lock a wheel. Practice and skill development is a big part of the reason why; good luck is another big part.
Finally, having ABS gives you the confidence to brake to the maximum. As I mentioned above, in the pre-ABS days, running the brake and escape exercise, I know I was always leaving a little of the motor's braking power on the table, for fear of locking a wheel. I was still successful, but not as confident as I could be. In my case this would manifest itself in uneven speed at the entry of the exercise. We're checked with radar, and 40 MPH is the correct speed to enter. A minimum of 38 MPH is required for a passing run. In the days before ABS my speeds would range from 38 up to about 43 MPH. Once I was able to take away the concern of locking a wheel, I was able to concentrate on dialing it in. My first exam on an ABS motor all four of my test runs were dead-on 40 MPH. My point is not simply to brag. Rather it's to illustrate that when you're braking to the threshold you have plenty to worry about. ABS allows you to concentrate on the important issues (evaluating the hazard, planning an escape route, downshifting to be in the proper gear should the hazard clear, etc) rather than simply concerning yourself with the mechanics of getting the maximum you can out of your brakes.
The technique of braking is exactly the same whether your motorcycle has ABS or not. The difference comes when the technique has failed. On a non-ABS motor it requires an immediate release and proper re-application, to handle a front wheel lock-up. That takes time, and time equals distance. It also takes a cool reaction to a hot situation. On an ABS motor, if the ABS activates, it IS an indication you've made a braking error. However, your response is simply keep pulling the lever, or pressing the pedal. As noted above, it will lengthen your braking distance, but by very little, and by far less than the method needed on a non-ABS motor. This means you can sit down later and consider how your braking error occurred, rather than letting the accident reconstructionist do it for you. (By the way if you have ABS, and you've felt it activate on the street, you should figure out what you're doing wrong in your braking, because you are doing something that can be improved).
So, the goal if you have ABS is to never know it's there. Just like all your other forms of insurance, and your other safety equipment. Unlike a helmet, a seat belt, an air bag, or car insurance, the beauty of ABS is it can jump in to prevent an accident, not just lessen the severity, or try to fix things later.
When you get the ABS motor, take it out to a parking lot and do some braking with it. Deliberately over-brake with the front and the rear, to activate the system in each. This way you'll know what it feels like, both in the lever/pedal, and how it makes the motorcycle behave (you'll feel the "brake-release-brake-release" as it modulates). The DVD that Harley provides with the ABS motors is well worth watching. It explains ABS, and it explains how the H-D system works and what you'll see and feel.
Finally, here are two videos:
Me on an ABS equipped motor (40 MPH entry speed):
And my friend David on a non-ABS motor (also 40 MPH entry):
It's the exact same exercise, run at the same speed. Hopefully you notice that the confidence imparted by the ABS allows me to run it a little more smoothly. However, the ABS system was not activated, and the motorcycle stops just as quickly as the non-ABS motor (in fact a little more quickly since the Brembos are a superior brake to the prior iteration).
Harris
Denver, CO
www.youtube.com/conedown
Cruiser
Joined: Aug 2008
Posts: 120
Likes: 0
well, if you really think about it, they kinda are. hit the front and rear brakes and abs will kick in if needed. hit the front brake only, and only front abs will work. turn it off? remove the fuse.....
hows that for advanced
i'm sorry, but thats just stupid. of course you aren't going to stop anywhere near in time just using your rear brake. the front brake provides 70% or more of your stopping power. abs or not, if you apply both brakes, you're going to stop quicker than just using your rear brake.....
hows that for advanced
i'm sorry, but thats just stupid. of course you aren't going to stop anywhere near in time just using your rear brake. the front brake provides 70% or more of your stopping power. abs or not, if you apply both brakes, you're going to stop quicker than just using your rear brake.....
Seasoned HDF Member
Joined: Feb 2007
Posts: 10,602
Likes: 721
From: Bellevue, NE
I have adressed this issue before. Harley has the worst ABS system in the industry. BMW being superior. I dont ride BMW, but I compete against them. That being said, Proper braking skills will save you every time. Uncle may have panicked and hit the rear brake only, which launch him into the intersection. just saying.
Tourer
Joined: May 2010
Posts: 368
Likes: 0
From: Dallas, Texas
I don't ride like I used to either. I am not a young man on cheap plastic crotch rocket. I am a little older (not old) riding a $40,000 bike that I love. I don't treat it the same way I used to treat my other bikes....for how I ride, ABS works for me on this Ultra Classic.
Road Master
Joined: Feb 2008
Posts: 903
Likes: 8
From: California
I have adressed this issue before. Harley has the worst ABS system in the industry. BMW being superior. I dont ride BMW, but I compete against them. That being said, Proper braking skills will save you every time. Uncle may have panicked and hit the rear brake only, which launch him into the intersection. just saying.
Last edited by Terrabella; Apr 27, 2012 at 09:20 AM.
Outstanding HDF Member
Joined: Jan 2011
Posts: 2,590
Likes: 31
From: Western Illinois, land of bad roads, and corrupt politicians
First, what are you basing your statement on that HD has the worst ABS system in the industry? Blanket statement without backup information. Secondly, I defy anyone who thinks they can out preform ABS brake system by " Proper braking skills". The statement is simply not true. Check the facts on ABS vs Non ABS
.There is a ton of research that proves the opposite and that ABS is a life saving device. Don't mean to rain on your parade but the facts and research prove you are safer on a motorcycle with ABS than not.
.There is a ton of research that proves the opposite and that ABS is a life saving device. Don't mean to rain on your parade but the facts and research prove you are safer on a motorcycle with ABS than not.
But you forgot to take into consideration, that they are superior internet denizens, and they race their touring bikes. With superhuman skills, that would shame a mere mortal. And we are not worthy to sniff their seats after they wow and amaze us with their prowess. And how dare you disagree with them, for they are the demigods of motorcycling.
I ride with a lot of cops......All of the LEOs that I ride with love their ABS.
Last edited by shooter5074; Apr 27, 2012 at 01:03 PM.
Club Member
Joined: Jun 2007
Posts: 3,435
Likes: 28
From: Living in open carry state :D
They should back up thier claims with a video of them on roads that are covered with the crap that is normally found out there. Then have to do emergency braking and manuvering without prior knowledge to they are truly emergency braking.
Road Master
Joined: Feb 2008
Posts: 903
Likes: 8
From: California
But you forgot to take into consideration, that they are superior internet denizens, and they race their touring bikes. With superhuman skills, that would sham a mere mortal. And we are not worthy to sniff their seats after they wow and amaze us with their prowess. And how dare you disagree with them, for they are the demigods of motorcycling.
I ride with a lot of cops......All of the LEO that I ride with love their ABS.
I ride with a lot of cops......All of the LEO that I ride with love their ABS.
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Elite HDF Member
Joined: Nov 2010
Posts: 3,846
Likes: 171
From: Simi Valley, CA
HDs wheel speed sensors use the wheel bearing to measure wheel speed. That bearing is only two inches in diameter. Most other systems use a seperate disc to measure wheel speed and that disc is much larger in diameter than the HD bearing. An example is a Yamaha wheel I have laying around with a four inch diameter disc. The larger the diameter of the disc that the wheel speed sensor is measuring, the more precisely it can measure wheel speed or any impending lock-up.
Because of the importance of aesthetics to HD and their owners, HD chose to incorporate the sensor into the wheel bearing. By doing so they succeeded in incorporating the ABS with very little visual impact to the bike, but in doing so, they also compromised performance to some degree.
That is one of the reasons the HD ABS is not as predictable, or efficient, as some other brands. Again, this is only my opinion.
Last edited by 2black1s; Apr 27, 2012 at 02:01 PM.