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Badger
New Member
21 Posts
rockville, md
USA
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 Posted - 02/16/2004 : 12:38 PM
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quote:
Originally posted by James R. Davis
Again, an imported thread that though it does talk about ABS, has an interesting side-bar that may be of interest: can you (or should you) brake and swerve at the same time believing that ABS equipped bikes make it less dangerous to do so.
ABS on motorcycles are designed to work with the motorcycle upright and going in a straight line. This is when a rider is most likely to apply maximum pressure on the brake controls. If a rider applies enough pressure on the brakes to lock a wheel, causing the ABS to activate, while leaned over in a turn/swerve, I'd suspect that rider is going down. The sudden changes in traction plus the on/off forces on the front and rear suspension systems will surely cause the rider to lose control. BMW warns against maximum braking while turning in their owners manual and they advocate rider training plus practicing proper braking techniques.
A professional rider who practices maximum braking on a daily basis probably will stop a non-ABS bike faster than an ABS equipped one. The average rider doesn't practice this skill often enough to be considered competent at this skill. Most riders don't want to wear out expensive tires by practicing rear wheel skids several times a week.
The California Highway Patrol considers ABS to be an important feature. Their cops train constantly and have skills far superior to the average rider, yet since they don't use maximum (near lock up) braking on a daily basis, they also lack the skills of a professional who gets to wear out tires on a track--a controlled environment.
City and rural streets aren't controlled environments. There is gravel, oil, anti-freeze, fuel, water, trash, salt, and other materials that can reduce traction. Even the pro who practices on clean and dry asphalt may discover that he/she has misjudged the amount of pressure to apply to the controls for a safe panic stop.
A rider who suddenly finds themselves in a situation with a locked wheel is very apt to panic and so something that will greatly decrease their chances of a good outcome. Even the pro may do something that decreases his/her chances of a good outcome. There's a difference between practicing hard braking on a track, where all you see past your braking point is more asphalt, than on a city street where you might be looking at the back end of a Mack truck.
Me, I like ABS. Just so you don't put me in the "inexperienced" catagory...I'm an MSF instructor...been riding 30 years and have over 500,000 miles under my belt. |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/16/2004 : 1:23 PM
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Jerry,
I appreciate your post and sentiments. I think, however, that you failed to read the complete thread. That is, if you went to the end of the topic you saw only a couple of message on second of two pages that contains the entire thread. I believe that if you had read the first page you would have a modestly different reaction to it. |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/16/2004 : 5:29 PM
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quote:
Originally posted by James R. Davis
Jerry,
I appreciate your post and sentiments. I think, however, that you failed to read the complete thread. That is, if you went to the end of the topic you saw only a couple of message on second of two pages that contains the entire thread. I believe that if you had read the first page you would have a modestly different reaction to it.
Yes, I did read the entire thread. Part of my response was to your last post (just above mine) and the other part was to your original question: "So, let me ask those of you that have ABS, or those of you who REALLY understand how it works, for your opinions." I'm stating my opinion to ABS.
I don't understand your comment that by reading the whole thread that I "would have a modestly different reaction to it." |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/16/2004 : 5:39 PM
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No, no ... I intended no criticism of your post - it was spot on. I thought that you might have read only the second page of the thread (you may not know it but I was importing the last four or five messages as you were making your post) and the defensive ending of your post which denied being a newbie left me wondering what you were responding to.
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/16/2004 : 5:56 PM
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quote:
Originally posted by James R. Davis
No, no ... I intended no criticism of your post - it was spot on. I thought that you might have read only the second page of the thread (you may not know it but I was importing the last four or five messages as you were making your post) and the defensive ending of your post which denied being a newbie left me wondering what you were responding to.
My last sentence was for anyone who claims that ABS is for the untrained or inexperienced rider. I've heard that one too many times. It wasn't in response to any particular post. |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/27/2004 : 11:54 AM
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quote:
Originally posted by James R. Davis
I have been rather steadfast in my refusal to accept ABS as a worthwhile addition to my motorcycle - not because I don't think it works, but because I think proper braking technique is more effective - and it is an expensive option.
However, I have also been virtually rabid in my admonishing to NEVER aggressively use your rear brake because of how easy it is to lock that brake and place yourself in a potentially deadly situation as a result.
Somewhere there is a compromise - that is, ABS is a godsend for inexperienced riders or those who simply will not practice braking techniques so that they find themselves having to 'learn' their braking limits in a panic situation. In those cases the expense of the option is of no concern.
So, let me ask those of you that have ABS, or those of you who REALLY understand how it works, for your opinions.
It is my understanding that ABS is not designed to help you stop in the quickest time and shortest distance. Rather, it is designed to help you avoid locking the rear brake. It does that by sensing when the rear wheel is spinning at a different (slower) rate than the front wheel is spinning (i.e., it is skidding.)
In such a case it releases brake pressure and allows the rear wheel to regain its traction, then QUICKLY restores braking pressure. In the past the speed with which the system responded was relatively slow - and the result was that there was NO BRAKING from the rear wheel for a relatively long time. Clearly that resulted in less than optimal braking, but it did avoid loss of control from a locked rear brake.
Subsequently these systems have been built with incredibly fast computers and sensors so that today's ABS systems no longer have that as a glaring deficiency. Still, I wonder. That is, if HALF the time (no matter how short the intervals) there is no braking pressure on the rear brake when the rear wheel is close to skidding then doesn't that mean that there is, on average, only 50% braking near its limits?
Granted that the physical reality is that you cannot remove brake pressure instantaneously and that therefore there is SOME (fading) brake pressure even in the half cycle where the system has 'removed' brake pressure, what is the effective braking rate over time? Is it close to 50%? More like 75%? Very close to 100%? (The closer to 100% the closer to optimal stopping performance.)
Anybody have any real-world experience and data to share with us?
Effective braking must be very close to 100% on my ABS equipped GS (Standard ABS. Not linked or power assisted). While grabing a handfull of front brake & standing on the rear brake, I can hear a light but steady squeal from the tires (clean, dry pavement, from 140kph).
I've tried a few different tests, from 140kph and dry pavement, once over painted surfaces and a few times while crossing sandy patches. The bike stayed steady and predictable at all times. Crossing over the paint & sand is a little unnerving at first, as the ABS lets off on the brakes, then comes back on. It feels like the brakes failed for a second, but it is just ABS saving your ass. It's important to keep in mind that the ABS does not release the brakes completely, but simply adjusts braking force to the availiable traction. That's a real bonus, since available traction can vary greatly over any real-life stopping distance.
Once my faith in ABS had built up enough, I tried overbraking in the rain, from 140kph. Same as above: the bike was steady and predictable with deceleration varying according to available traction. Way cool!
With proper braking technique, defensive driving and yadayadayada, this is exactly the same as driving a Non-ABS bike until that Volvo jumps out in front of you and, in that second or two before impact, you are doing everything right (come onto the brakes, reduce braking at the rear and increase at the front while the weight shifts to the front wheel, modulating brake pressure to the front and rear as you feel a skid start on either wheel all the while looking for a safe place to squeeze by the car and other moving or stationary objects, and of course, staying calm, cool and collected) but somehow failed to see that bit of sand or painted line or oil. That's where ABS comes in.
I agree that it can seem like an expensive option, but with $20k worth of bike, $2000 of protective gear and the precious cargo abord the bike, investing $1000 into ABS is a no-brainer: if you use it only once, it just paid for itself many times over.
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/27/2004 : 10:26 PM
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I had the unfortunate opportunity to use maximum braking (or panic braking,take your pick)& a change of direction when a pickup suddenly pulled into the right lane I was merging into.I stopped right next to the right curb just at the point the lanes merged.In hindsight,I didn't make a classic serve ,but a quick shift to the right side of the lane as I started braking.So I did not use all the available traction for changing direction or braking.
I think in an emergency situation,it would probably be impossible to combine a classic hard serve with hard braking.To serve out of the way of an object ,the bike has to be able to roll forward in the new direction.When a racer uses a rear slide to turn a bike,it doesn't move forward in the new direction until the wheel catches traction to move the bike in that direction.If not,then the bike continues to slid towards the object.This I know from another unfortunate opportunity. |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 02/28/2004 : 8:41 AM
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I don't have experience with ABS on a motorcycle, but I do have experience driving a 2000 corvette for a few years. Many posts in this thread keep focusing on comparisons of stopping distance between ABS and non-ABS-equipped vehicles under ideal driving conditions. The point of ABS has nothing to do with reducing the stopping distance of the vehicle, it has to do with maintaining directional control when traction is lost!
Thus, in adverse conditions such as a sandy corner, where my 'vette has "jumped" to the side while braking and turning, the ABS allowed the front tires to turn in the intended direction of travel, maintaining the alignment of the vehicle in the proper desired lane. In an extreme situation under the same condition with a non-ABS equipped vehicle, it would have been more likely that the average driver would have slid sideways into oncoming traffic or a curb. I have experience driving that car on the track at Sears Point Raceway (before they radically changed it), in autocross and on the roads.
James quotes a statistic that indicates more single-vehicle accidents result with ABS equipped vehicles because their drivers lose control. I surmise that these same drivers while driving a non-ABS car would have also ended up in the ditch. ABS doesn't compensate for a driver that overcorrects -- that's what ACTIVE HANDLING is for on a car, a system that independandly brakes one of four wheels on the appropriate corner of the car to maintain sticktion. ABS, when used properly by a driver who is in control, provides an advantage of being able to redirect the vehicle under adverse braking conditions.
I mentioned I autocrossed the 'vette. Exiting a right curve too fast at one point, I headed straight for the cones and braked fully. My ABS kicked in and I ended up knocking over 2 cones as a result - in this situation I believe without ABS I could have stopped short of the cones and not suffered the point deduction. ABS does not decrease stopping distance. It aids in directional handling under adverse braking conditions. The folks that have claimed that swerving under braking conditions with ABS on their motorcycles are supporting this statement.
Controlled driving, braking and knowing the vehicles limits in cornering are the best defense against an accident. Technology like Active Handling and ABS are last resorts.
By the way, great thread! |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 03/02/2004 : 6:17 AM
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Avatar makes a lot of great points and is spot on with his comment that ABS is ultimately to maintain directional control - for a CAR. ABS on a motorcycle performs another critical function. When a motorcycle's wheels are locked, all the natural physics that work to keep the motorcycle in a wheels down attitude end. Yes, through movement and steering inputs the rider contributes to balance; but with the front wheel locked there's no more steering. So, on a motorcycle, ABS also plays the critical role of keeping the bike upright by keeping the wheels turning at a rate relatively appropriate to the speed of the bike. IMHO, there might be a marginal improvement in the ability to panic brake and swerve with ABS, but I'm not eager to try it out on my GL1800. I think the benefit is primarily to provide optimal braking in a panic situation with lots of potential variability: changing traction conditions (as mentioned above) and proficiency of the rider. With only 60,000 road miles, most of you guys totally eclipse me in street experience. However, I also have that many miles with serious off-road. I know highside/lowside dynamics through experience  and I know how to stop and turn a motorcycle in all imaginable traction conditions (including ice riding)  off road. I wouldn't give up my ABS for anything on my Goldwing. I want every possible advantage. Undoubtedly an expert can out-stop ABS in controlled conditions, but in the chaos or a panic stop situation on the road, my judgment is ABS will give me a safety edge.  |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 05/20/2004 : 1:33 PM
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| Hello to all yee speptical about ABS on a motorcycle, I ride a BMW R1150GS with ABS. ABS (at least on my bike) works beatifully, it is a hundred times safer in any braking situation and gives me more braking flexability in general. ABS will however kill you on the dirt so you need to be able to turn it off as you can on Beemers. Those miliseconds of brake release are not even noticable and feel much better than a cycle skiding (sideways eventually!) down the highway. My bike is a 2003 and I have never ridin another bike with ABS so I dont know how much it varies from maker to maker? |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 05/20/2004 : 4:30 PM
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| Notwithstanding the apparent statistical superiority of ABS equipped machines, at least in some situations, one of the unspoken benefits is that most of the owners seem to be fond of it and are confident that it works to their benefit... good deal. That’s the way we all should feel about our rides... I’ve whacked the brakes pretty hard on my Nad, and those suckers have hauled down a load approaching 1450#s quickly enough to make the forks go to full compression -- no skids, no slides, nuthin’ went thump in the night and the wheels stayed under her... And other than nearly having my navigator up around my ears, no drama... I have since jettisoned the navigator and can lock the rear wheel again, so maybe ABS is for solo riders... although navigators can do some things that ABS can’t, so I’m negotiating for a replacement (navigator, not ABS). In any case, I’m happy with my ride... works fer me... can I ask for more. Nope... |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 05/21/2004 : 9:57 PM
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This just in from a Goldwing mail list: in the Minnesota Motorcycle Monthly June 2001 edition, there's article giving stats on the new Goldwings, including braking with and without ABS. They're -- interesting, to say the least. 
Stats:
Horsepower 118HP at crank, 104HP at Rear wheel @5,500 rpm
Torque 125(lbft) at crank, 110(lbft) at rear wheel @ 4,250 rpm
1/4 Mile, 12.34s @ 105.84MPH
0 to 60 MPH, 4.14 seconds.
0 to 30 MPH, 1.22 seconds.
Top gear roll on, 40 to 60 MPH, 4.59 seconds.
60 to 80 MPH, 5.42 seconds.
Braking, 60 MPH to 0 with ABS, 149.4 ft.
Braking, 60 MPH to 0 without ABS, 143.5 ft.
Braking, 30 MPH to 0 with ABS, 30.6 ft.
Braking, 30 MPH to 0 without ABS, 31.4 ft.
One does wonder how these distances were derived, and why the different results with ABS at higher and lower speeds...??
Cash |
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 05/23/2004 : 4:35 PM
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quote:
Originally posted by Cash Anthony
This just in from a Goldwing mail list: in the Minnesota Motorcycle Monthly June 2001 edition, there's article giving stats on the new Goldwings, including braking with and without ABS. They're -- interesting, to say the least.
Stats:
Horsepower 118HP at crank, 104HP at Rear wheel @5,500 rpm
Torque 125(lbft) at crank, 110(lbft) at rear wheel @ 4,250 rpm
1/4 Mile, 12.34s @ 105.84MPH
0 to 60 MPH, 4.14 seconds.
0 to 30 MPH, 1.22 seconds.
Top gear roll on, 40 to 60 MPH, 4.59 seconds.
60 to 80 MPH, 5.42 seconds.
Braking, 60 MPH to 0 with ABS, 149.4 ft.
Braking, 60 MPH to 0 without ABS, 143.5 ft.
Braking, 30 MPH to 0 with ABS, 30.6 ft.
Braking, 30 MPH to 0 without ABS, 31.4 ft.
One does wonder how these distances were derived, and why the different results with ABS at higher and lower speeds...??
Cash
Interesting stats. Braking performance is almost identical (ABS verses non-ABS). Due to variation in testing I wouldn't conclude or read too much into the differences presented. They seem identical to me. If I were buying a bike with an ABS option I would highly consider buying it. I just don't have much information concerning maintenance and failure costs on ABS. Except for BMW, and maybe the Honda ST, there probably isn't very much information to go on. Anyone seen a discussion about this anywhere else?
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 05/23/2004 : 4:46 PM
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quote:
Originally posted by James R. Davis
This can go on forever - with clarifications ad nausea. I hope this makes clear *MY* black/white thinking:
If you cannot avoid an accident with maximum braking and you cannot avoid the accident by maximum swerving, then BY DEFINITION any combination of the two means that you CANNOT AVOID THE ACCIDENT and that you will collide moving faster than had you merely used maximum braking.
I'm going to have to think about this comment. Do you stand by it for a moving hazard also? This will probably be a purely academic discussion though. You usually have back up for your statements. Scenario: Maximum braking to cut your speed in half followed by a swerve. Cutting your speed in half now reduces the centripatal force by 75% when you start and do your swerve. How does that impact the swerve angle you can take to miss the obstacle? I haven't worked out the math. Have you? Once again, I'll have to sit down and figure this out.
;)
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Badger
New Member
21 Posts
rockville, md
USA
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Posted - 09/06/2005 : 12:11 PM
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| Recovered from Archive today. |
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rioguy
Ex-Member
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Posted - 06/07/2009 : 6:53 PM
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I added this to an old thread as it's interesting to see how our opinions might have changed.
My new Burgman 650 is identical to my old one except for a few minor differences. It has an electrically adjustable windscreen, a backrest for a passenger, mirrors that fold in electrically and ABS braking.
Today, I practiced braking with it the first time. It was under what I consider to be ideal surprise conditions. Neibor and I were playing some follow the leader in the parking lot. I was offset well to the side and behind as we had gotten separated a bit and with out warning after looking back, he braked pretty hard. I braked at the level I normally would for threshold braking and felt the ABS cycle about 6 times. I don't know if it was the front or the rear that cycled. When I looked back, I didn't see the incipient skid I usually leave in threshold braking.
Given my experience on the old Burgman which carries over to the new one, I'd have to say the stopping distance was likely very slightly farther.
Shortly after, it started to hail, so we took shelter. After it stopped, we started out again. Then it started to hail again. Not bad enough so the road was hazardous to ride on, but the surface would have been totally unpredictable if I had to stop. I was glad to have the ABS then.
In my opinion, which I'll likely test some time, a bike without ABS with a rider who has practiced braking can likely stop sooner than one with ABS UNDER IDEAL CONDITIIONS. I.E. a dry road. However, most riders would likely be able to stop quicker under all conditions. An experienced rider would likely be able to stop both more quickly and more safely under less than ideal conditions.
One could make the argument that the experienced rider can feel the brakes approaching lock. I would agree with that for the conditions the rider has practiced in. But how easy is it to find a time to practice on a road that is maybe 15% hail covered? Or wet oil approaching an intersection?
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rioguy
Ex-Member
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Posted - 06/08/2009 : 8:49 AM
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I found this article on ABS which was released by the Insurance Institute for Highway Safety in March 2009.
The title suggests those who have ABS have a 28% lower fatality rate.
One is fallacy is expressed on page 7.
"The substantial effectiveness estimate observed in this study is not, however, without limitations.
ABS was studied as optional equipment, so the cohort of motorcyclists who choose to purchase ABS may differ from those who decline to purchase it. In particular, motorcyclists who choose ABS may be more
concerned about safety than those who decline,"
A conclusion I could draw from the article is 28% of the fatalities are caused by less than optimum braking (perhaps resulting in a skid or a greater than optimum stopping distance.)
Be sure to scroll past the references to the tables on pages 12 and 13.
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tmonroe
 Advanced Member
693 Posts
[Mentor]
Seattle, WA
USA
Kawasaki
ZX-10R
Peer Review:
2
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Posted - 10/29/2009 : 1:16 PM
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I guess this is as good a thread as any to admit to a new motorcycle purchase. Actually two.
I traded in my GL1800 and my wife traded in her VFR800 for a pair of 2008 FJR1300s. (We've now had them for about 5 months). For me, one of the requirements of the new bikes was that they had ABS.
My wife and I are both MSF instructors (both of us teach part-time typically 2 weekends a month). Besides the regular practice that we get doing demos when we teach a class, we both regularly practice braking, and I've also setup G-force meters on several bikes and made hundreds of practice braking runs at the "park and ride" near our house in conditions varying from clear and dry to packed ice (packed ice not so much).
That being said, in 8 years of street riding in often heavy traffic (probably on the order of 70,000 miles) , I can only remember having to use emergency braking once. At the instant I did have to brake, I remember distinctly thinking that my hand was applying the brake too slowly. In retrospect, I was braking properly, but my mind was in a sort of panic wanting the brakes to be applied sooner. Fortunately for me, the training won over, and although I did a "panic stop", I really never got that close to the vehicle in front of me (which was skidding along and hit the vehicle in front of it).
From my experience as an instructor, when I see students "panic", that they lose the ability to sensibly use the controls as their panic takes over, and they begin to do things like grab the brakes and try to stop the bike by dragging their feet. I believe in my "close call", my experience was the exact opposite. From a large amount of practice, I found myself doing the correct thing although my mind was in a state of relative panic (things were happening very fast, and I felt a little distress that it seemed like I was not applying the brake as quickly as I wanted).
So if I've proven to myself that in a bad situation that even if I feel some degree of panic, that I'll still use the brakes properly why would I still want ABS? Because I think if the pavement had been wet, or otherwise traction had been compromised, that I probably would not have released the brake and reapplied it. I think in order to get to that level of proficiency in my own riding, I would need more practice doing that. Although I have locked up the front brake several dozen times, I don't think its enough to know for sure what I'd do in a real-life situation with a variety of other sensory input. Under some situations, you can slightly manually outbrake a bike with ABS, but if the rider doesn't quickly detect that the front tire is skidding, a bike can go down fairly quickly with a locked front wheel.
On a bike equipped with ABS, the ABS doesn't effect braking until the tire slides. Except for the rare case of trying to make an emergency stop on something like gravel, that means that in all other cases, having ABS is at least as good as not having ABS - and in any given stop, if the brake locks, the rider is at serious risk (even if they otherwise won't hit anything) without ABS if they don't react quickly. Another way to look at it: The fact they overused the front brake is an indication that they are using improper braking technique - why would you expect them to perform an even more complicated braking technique just as they percieve that the level of danger has increased?
On the FJR, ABS is standard, and the FJR was one of the cheapest Sport-touring bikes available. I think maybe a few years ago, the cost argument had some validity, but now that bikes like the FJR come with ABS standard, its harder to make a case against it.
Now that ABS is nearly ubiqitous on some types of bikes, it will be interesting to see if motorcycle crash studies will show any indication of improved safety. |
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gymnast
Moderator
2805 Posts
[Mentor]
Meridian, Idaho
USA
Harley-Davidson
Sportster Sport
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Posted - 10/29/2009 : 8:41 PM
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| That's an good summary of the reasons to have ABS on any motorcycle and you do an excellent job of articulating the reasons why I will have ABS on the next motorcycle that I buy. Having a braking system that can be operated at 98% when one is having a "70% day" at the same time that an "85% emergency" arises is a good reason to have ABS. |
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