Abs
#1
01-26-2013, 04:41 PM
Abs
I am still new to the Harley big bikes (2009 Ultra Classic) and was practicing my slow drills and braking. I was braking hard at 30-40mph for practice and toward the end of the braking/stopping I consistently heard some noise. I assume this is the ABS coming on/off. Hard to describe the sound I was hearing but it was only when I braked hard. Thanks for your help.
#2
01-26-2013, 04:53 PM
Seasoned HDF Member
#3
01-26-2013, 05:42 PM
It's impossible to say for sure from your description, but...
You only mention what you hear, and not that you feel anything. The H-D ABS system is designed to have a particularly strong pulse in the lever/pedal; so you would likely feel that.
You mention it's right at the end of your braking. All ABS systems disable at very low speeds. They have to work this way, or the end of every stop would be very long. One consequence of this is that, once the motor is at that low speed (less than 3-5 MPH), ABS is inactive, and thus you can get a moment's skid, with the accompanying noise. At that speed - particularly if it's the rear wheel (which is the more liley anyway), you won't feel anything from a locked tire, and it's not really hurting anything.
Harris
Denver, CO
www.youtube.com/conedown
You only mention what you hear, and not that you feel anything. The H-D ABS system is designed to have a particularly strong pulse in the lever/pedal; so you would likely feel that.
You mention it's right at the end of your braking. All ABS systems disable at very low speeds. They have to work this way, or the end of every stop would be very long. One consequence of this is that, once the motor is at that low speed (less than 3-5 MPH), ABS is inactive, and thus you can get a moment's skid, with the accompanying noise. At that speed - particularly if it's the rear wheel (which is the more liley anyway), you won't feel anything from a locked tire, and it's not really hurting anything.
Harris
Denver, CO
www.youtube.com/conedown
#4
01-26-2013, 08:42 PM
Keith I am practicing very fast stops so I can be prepared to stop quickly. With my normal braking I do not hear or feel the ABS kicking in. I didn't explain it very well but it happens as soon as I clamp down hard on the front and rear brake at the same time. So it really isn't at the very end of the stop. If I am going 30 mph and I hit the brakes hard (again, learning how quickly I can stop the big bike), right after that is when I hear and feel the grabbing of the brakes (or at least that is what I think is happening) and it makes kind of a "rattling" noise as it is grabbing. Best that I can explain it.
#5
01-26-2013, 08:46 PM
It's impossible to say for sure from your description, but...
You only mention what you hear, and not that you feel anything. The H-D ABS system is designed to have a particularly strong pulse in the lever/pedal; so you would likely feel that.
You mention it's right at the end of your braking. All ABS systems disable at very low speeds. They have to work this way, or the end of every stop would be very long. One consequence of this is that, once the motor is at that low speed (less than 3-5 MPH), ABS is inactive, and thus you can get a moment's skid, with the accompanying noise. At that speed - particularly if it's the rear wheel (which is the more liley anyway), you won't feel anything from a locked tire, and it's not really hurting anything.
Harris
Denver, CO
www.youtube.com/conedown
You only mention what you hear, and not that you feel anything. The H-D ABS system is designed to have a particularly strong pulse in the lever/pedal; so you would likely feel that.
You mention it's right at the end of your braking. All ABS systems disable at very low speeds. They have to work this way, or the end of every stop would be very long. One consequence of this is that, once the motor is at that low speed (less than 3-5 MPH), ABS is inactive, and thus you can get a moment's skid, with the accompanying noise. At that speed - particularly if it's the rear wheel (which is the more liley anyway), you won't feel anything from a locked tire, and it's not really hurting anything.
Harris
Denver, CO
www.youtube.com/conedown
#6
01-26-2013, 09:10 PM
t
This is a little outside of the discussion, however, don't "clamp down". It's meant to be a continuous squeeze, firm in nature. Yes, quick, but not in a panicky grabbing kind of way. If you're practicing for real world, ABS or not, that is the correct procedure. Not stabbing at the brakes.
I applaud you practicing, it's a great thing. ABS is a wonderful thing, IMHO, but being able to hit threshold braking without initiating ABS is one of the greatest riding skills in your arsenal.
The description you're providing tends to make me think you may be using more of stabbing, grabbing a handful of brakes style in your practice. Remember to use a good, strong continual four finger squeeze of your front brake. If you keep your foot on the rear brake pedal as you do this, the inertia that will put your weight forward will put the appropriate pressure on the pedal, you just follow through with that pressure as opposed to stomping on it a'la a car brake.
Harris, please chime in if you think I'm off base. (I certainly bow down to a Motor Officer instructor.... we simple MSF instructors are not worthy!!
)
Keith I am practicing very fast stops so I can be prepared to stop quickly. With my normal braking I do not hear or feel the ABS kicking in. I didn't explain it very well but it happens as soon as I clamp down hard on the front and rear brake at the same time. So it really isn't at the very end of the stop. If I am going 30 mph and I hit the brakes hard (again, learning how quickly I can stop the big bike), right after that is when I hear and feel the grabbing of the brakes (or at least that is what I think is happening) and it makes kind of a "rattling" noise as it is grabbing. Best that I can explain it.
I applaud you practicing, it's a great thing. ABS is a wonderful thing, IMHO, but being able to hit threshold braking without initiating ABS is one of the greatest riding skills in your arsenal.
The description you're providing tends to make me think you may be using more of stabbing, grabbing a handful of brakes style in your practice. Remember to use a good, strong continual four finger squeeze of your front brake. If you keep your foot on the rear brake pedal as you do this, the inertia that will put your weight forward will put the appropriate pressure on the pedal, you just follow through with that pressure as opposed to stomping on it a'la a car brake.
Harris, please chime in if you think I'm off base. (I certainly bow down to a Motor Officer instructor.... we simple MSF instructors are not worthy!!
)
Last edited by zion; 01-26-2013 at 09:14 PM. Reason: spelling
#7
01-26-2013, 10:31 PM
t
This is a little outside of the discussion, however, don't "clamp down". It's meant to be a continuous squeeze, firm in nature. Yes, quick, but not in a panicky grabbing kind of way. If you're practicing for real world, ABS or not, that is the correct procedure. Not stabbing at the brakes.
I applaud you practicing, it's a great thing. ABS is a wonderful thing, IMHO, but being able to hit threshold braking without initiating ABS is one of the greatest riding skills in your arsenal.
The description you're providing tends to make me think you may be using more of stabbing, grabbing a handful of brakes style in your practice. Remember to use a good, strong continual four finger squeeze of your front brake. If you keep your foot on the rear brake pedal as you do this, the inertia that will put your weight forward will put the appropriate pressure on the pedal, you just follow through with that pressure as opposed to stomping on it a'la a car brake.
Harris, please chime in if you think I'm off base. (I certainly bow down to a Motor Officer instructor.... we simple MSF instructors are not worthy!!)
This is a little outside of the discussion, however, don't "clamp down". It's meant to be a continuous squeeze, firm in nature. Yes, quick, but not in a panicky grabbing kind of way. If you're practicing for real world, ABS or not, that is the correct procedure. Not stabbing at the brakes.
I applaud you practicing, it's a great thing. ABS is a wonderful thing, IMHO, but being able to hit threshold braking without initiating ABS is one of the greatest riding skills in your arsenal.
The description you're providing tends to make me think you may be using more of stabbing, grabbing a handful of brakes style in your practice. Remember to use a good, strong continual four finger squeeze of your front brake. If you keep your foot on the rear brake pedal as you do this, the inertia that will put your weight forward will put the appropriate pressure on the pedal, you just follow through with that pressure as opposed to stomping on it a'la a car brake.
Harris, please chime in if you think I'm off base. (I certainly bow down to a Motor Officer instructor.... we simple MSF instructors are not worthy!!
)Trending Topics
#8
01-26-2013, 11:34 PM
Zion is 100% spot on.
Now that you've filled in the details, I'm fairly certain you are getting into ABS on the front, then backing out of your brake application, likely because you "feel something wrong". You're ending up with pretty decent braking, but you're practicing a bad habit; so lets try to get you on a better path.
As Zion pointed out, the key to properly applying the front brake is to slow it down enough to allow the motor's weight to transfer. If you grab the front brake, the stopping force to the front wheel is applied when roughly half the machine's weight is on the front tire. It's very easy for the brakes - especially the Brembo brakes, which are extremely powerful - to transmit more stopping force that the friction between the tire and road can use. If you don't have ABS, this results in a locked-wheel skid. If you do have ABS, it activates.
So, the answer is to slow down the application ever so slightly. This is done with the "squeeze and progress" technique. Initially squeeze the lever. There is no "magic amount", which is why you have to practice. This initial "squeeze" causes the motorcycle's weight to transfer forward. With very little practice you will feel this occur. Then you "progress" your squeeze, increasing the brake's transmission of stopping force. This is the most efficient way to get the motorcycle stopped. It's also the correct technique whether your machine has ABS or not. On the newer Harleys, with the Brembo brakes, you will really know when you're braking well, because you will feel your own weight transfer forward. Braked properly the newer Touring models will stop far better than most riders would believe.
Mind you, the "squeeze and progress" is still a rapid application of the brakes. It's just that you consciously take steps to make the machine do what you want. This is why it's "threshold" braking, not "panic" braking. You practice, and then use your skills to take the stopping force to the threshold of friction available on whatever your road surface is.
It is tempting - on a motor equipped with ABS - to forgo proper braking, and just let the ABS do the work. However, that will not get you stopped nearly as quickly as proper braking. Considering the whole point of this type of braking is to avoid colliding with a suddenly present obstacle (I'm looking at you soccer mom making a left turn in front of a motorcycle) it only stands to reason you want to do all you can to stop in the absolute shortest possible distance.
I've posted this video before, but it really fits in with this exact topic. The motor nearer the camera is stopped using the "squeeze and progress" method, and ABS does not activate. The far motor's rider makes no attempt to brake correctly, and instead simply "grabs a handful of brake". By snapping on the brakes that way, he doesn't allow any weight transfer to take place. Therefore ABS activates immediately. You can see how much that increases the stopping distance (it helps to watch the video in full screen):
What it sounds like you're doing is snapping the front on, and consequently getting ABS, then backing out, but not all the way, thus getting into better braking. There are two problems with that. One is - as we've discussed - it's not very efficient. Two is that you're training yourself to back off if you activate ABS. If ABS does activate, the rider's best course at that point is to keep pulling on the lever, and let the ABS handle the stop.
In training we teach operators to handle front ABS activation like a locked-wheel skid on a non-ABS motor; that is to "release immediately and properly re-apply". However, that is strictly because we're working to build proper skills. On the street, if ABS engages, let it do it's thing. Now as I often say (and sometimes upset people by saying) if a rider activates ABS he has made a braking error. If ABS activates, you would have locked a wheel without ABS. A locked wheel is a braking error. ABS just makes it so you can think about how you could improve your braking at leisure, and without the expensive or painful outcome that a skid often results in.
Harris
Denver, CO
www.youtube.com/conedown
Now that you've filled in the details, I'm fairly certain you are getting into ABS on the front, then backing out of your brake application, likely because you "feel something wrong". You're ending up with pretty decent braking, but you're practicing a bad habit; so lets try to get you on a better path.
As Zion pointed out, the key to properly applying the front brake is to slow it down enough to allow the motor's weight to transfer. If you grab the front brake, the stopping force to the front wheel is applied when roughly half the machine's weight is on the front tire. It's very easy for the brakes - especially the Brembo brakes, which are extremely powerful - to transmit more stopping force that the friction between the tire and road can use. If you don't have ABS, this results in a locked-wheel skid. If you do have ABS, it activates.
So, the answer is to slow down the application ever so slightly. This is done with the "squeeze and progress" technique. Initially squeeze the lever. There is no "magic amount", which is why you have to practice. This initial "squeeze" causes the motorcycle's weight to transfer forward. With very little practice you will feel this occur. Then you "progress" your squeeze, increasing the brake's transmission of stopping force. This is the most efficient way to get the motorcycle stopped. It's also the correct technique whether your machine has ABS or not. On the newer Harleys, with the Brembo brakes, you will really know when you're braking well, because you will feel your own weight transfer forward. Braked properly the newer Touring models will stop far better than most riders would believe.
Mind you, the "squeeze and progress" is still a rapid application of the brakes. It's just that you consciously take steps to make the machine do what you want. This is why it's "threshold" braking, not "panic" braking. You practice, and then use your skills to take the stopping force to the threshold of friction available on whatever your road surface is.
It is tempting - on a motor equipped with ABS - to forgo proper braking, and just let the ABS do the work. However, that will not get you stopped nearly as quickly as proper braking. Considering the whole point of this type of braking is to avoid colliding with a suddenly present obstacle (I'm looking at you soccer mom making a left turn in front of a motorcycle) it only stands to reason you want to do all you can to stop in the absolute shortest possible distance.
I've posted this video before, but it really fits in with this exact topic. The motor nearer the camera is stopped using the "squeeze and progress" method, and ABS does not activate. The far motor's rider makes no attempt to brake correctly, and instead simply "grabs a handful of brake". By snapping on the brakes that way, he doesn't allow any weight transfer to take place. Therefore ABS activates immediately. You can see how much that increases the stopping distance (it helps to watch the video in full screen):
What it sounds like you're doing is snapping the front on, and consequently getting ABS, then backing out, but not all the way, thus getting into better braking. There are two problems with that. One is - as we've discussed - it's not very efficient. Two is that you're training yourself to back off if you activate ABS. If ABS does activate, the rider's best course at that point is to keep pulling on the lever, and let the ABS handle the stop.
In training we teach operators to handle front ABS activation like a locked-wheel skid on a non-ABS motor; that is to "release immediately and properly re-apply". However, that is strictly because we're working to build proper skills. On the street, if ABS engages, let it do it's thing. Now as I often say (and sometimes upset people by saying) if a rider activates ABS he has made a braking error. If ABS activates, you would have locked a wheel without ABS. A locked wheel is a braking error. ABS just makes it so you can think about how you could improve your braking at leisure, and without the expensive or painful outcome that a skid often results in.
Harris
Denver, CO
www.youtube.com/conedown
Last edited by motorlessons; 01-26-2013 at 11:42 PM.
