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Thread: "ABS" has been misnamed from day one

  1. #1
    Nickname: Droid
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    "ABS" has been misnamed from day one

    There have been numerous articles on the effectiveness of ABS systems on cycles, to help the rider maintain control when braking in a straight line. But, I have never seen an article or video, relative to the limited capabilities of ABS on a cycle when the bike is leaned into a turn, or when swerving. But, many videos of ABS stops of cars also show the car being "steered" around an obstacle as part of the capabilites of the system. When a bike is leaned into a turn, lots of traction is being used. Current ABS systems only function once a wheel is braked, and that braked wheel must already be slightly past the traction thresehold (about 10% to 20). Most all of us know that combination is NOT good when leaned into a turn. Yet I bet many riders assume the ABS on their cycle will cover their butt if they loose control in a turn while braking, just like with the ABS in their car.

    A huge influence on the misperception of ABS is in the name itself "Antilock Braking System". Everyone assumes it is a braking system, or a braking assist system, which it is NOT. Had it been called a "Stability Assist System" from day one with no reference to braking, then perhaps over time the car drivers and bike riders would not first think of ABS as a braking system.

    "Stability", whether applied to the dynamics of a car or motorcyle, in essence means the operator is able to maintain control over the vehicle. But especially on a motorcycle, stability also means the bike must first remain upright, or at least in a manner enough for the rider to maintain control. For example: a rider power sliding through a turn, the bike can be leaned over a LOT, and countersteered a LOT, but yet the bike is stable because the rider has control. So the FIRST and PRIMARY function of ABS on cycles is to maintain stability/control, and in so doing the current ABS systems only fulfill this directive when the bike is stopped in a straight line and nearly always fully perpendicular to the road surface.

    When we consider traction control systems for high performance riding, its been proven on race tracks that for a bike to really be fast through the turns the rider must be able to spin/slide the rear tire, sometimes with the rear of the bike stepping out. Traction Control, as a stability control, actually limits the rider's ability, if indeed the rider is skilled enough to power slide on dry pavement through turns.

    So back to ABS, it is ONLY a stability assist system. In that context, riders really should not expect the ABS system to overcome their mistakes and inabilities relative to maintaining control while leaned into a turn and applying brakes. Because it all comes down to the traction limits. If the rider exceeds the traction limits while leaned/turning, the ABS system very likely cannot always assist the rider to maintain or regain control. Remember, for ABS to even engage, the rider first has to be on the brakes, and the tire has to slightly exceed the traction thresehold,. That combination is not a function of "stable" riding for most of us.

  2. #2
    Registered User lkchris's Avatar
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    Comparisons to cars are apples/oranges of course and not very relevant.

    "Losing control" in a curve with a motorcycle essentially means you've fallen down and it's obvious brakes don't prevent that. But, if you're not quite to that point and slowing down can help, ABS is good and brake locking isn't.

    Moving on ... with cars, the ABS functions can be turned around to prevent wheel spin, making limited slip differentials a bit old fashioned for example. And on cars traction control systems tied to the brakes can essentially detect when the car is not tracking straight and can even control trailer sway. Also all obviously not relevant to bikes.

    More interesting, perhaps, are the traction control systems--called ASC on BMW motorcycles (automatic stability control)--where the electronic sensors talk to engine control rather than a brake fluid pump and prevent loss of traction due to the engine overpowering the rear tire's ability to cope. This CAN without question help you on a motorcycle in a curve.
    Kent Christensen
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    It's a way of life! oldnslow's Avatar
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    Am I missing something here?

    Antilock Brake System. A system that prevents the brakes from locking up. Doesn't imply stability control to me. Although, if my front wheel is not skidding in a panic stop, I will have control.
    Mike Davis
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    MearthA rdalland's Avatar
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    ride what you've got; enjoy the road you're on!

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    Fourcats
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    THAT is funny!

  6. #6
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    Mike, to your comment, "Antilock Brake System. A system that prevents the brakes from locking up. Doesn't imply stability control to me." If a braked wheel skids, and the bike looses balance and dumps, that is a loss of stability. If the rider applies too much throttle in a turn, and the rear wheel slides out and the bike dumps, that is a loss of stability. So both ABS and Traction Control are really stability assist systems. A bike is only stable when moving if the rider has control. Or if the bike is stationary and parked on the sidestand or centerstand. So, maybe I need to clarify this a bit further:

    Yes, ABS is a system to keep the brake from locking up. BUT, the key factor is that to "initiate" ABS control on a wheel/brake, two things have to happen together:
    1. The brake must be applied on that wheel. So the rider must first apply brake pressure. With no brake pressure applied to the wheel, the ABS is doing nothing but monitoring wheel speed.
    2. The wheel HAS to slightly break traction, slip, skid, to get ABS control to start. ABS control logic is based on the wheel jexceeding traction by a preset amount before ABS control even starts.

    It is that initial "break traction" aspect of ABS control that is the problem for bikes when they are leaned over into a turn. In a straight line, if the tire skids for a fraction of a second, the bike can still be controlled. But in a turn, or leaned over, even that fraction of a second "may" be enough to loose stability. Or perhaps the bike doesn't fall over in that brief moment. But then if it suddenly gains traction when leaned over, the results can be violent enough to throw the rider off the bike. That is why I would like to see tests of an ABS equipped bike (with outriggers), brakes over applied in a curve, to see how the bike and ABS system reacts. I may be wrong about the results, but if so I'd like to see that proven.

    Also, every ABS engineer I have talked to all refer to ABS systems as stability control systems and not as braking systems. They assist stability control by using the brakes.

    Mike, based on your response I'm curious: do you feel that onn a bike with ABS that you could apply all the brakes you want in a turn while leaned over, and expect the ABS to not let a wheel lock up? Because in that expectation you would assume you'd not loose control?

    Ikchris, your comment puzzles me, "But, if you're not quite to that point and slowing down can help, ABS is good and brake locking isn't." Because your comment says what I think a lot of people expect of ABS systems: that being an expectation that ABS helps in all braking conditions. Well, ABS ONLY helps when the braked tire HAS LOST TRACTION. Until that happens, ABS does nothing to help the rider. Until traction is lost on the wheel being braked, it is NO different than on a bike without ABS. That is the problem of perception of what ABS systems do.

    Now don't think I am bad-mouthing ABS systems, or that I feel I can out-perform any ABS system because of my "expert skill level" because neither is the case. I have owned an ABS equipped bike for 17 years, and even repaired the ABS system after it failed to make sure it would still help me when needed. But, we have to be aware of what ABS systems can and cannot do.
    Last edited by ANDYVH; 12-16-2011 at 03:57 PM.

  7. #7
    God? What god? roborider's Avatar
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    I see your point, but obviously you shouldn't be braking in a corner anyway (other than some trail braking). Most problems in a corner, which is the fear of running wide due to too much entry speed, can be solved by leaning much harder. Very few riders ever lean as much as the bike can lean, thus low-siding. You see it all the time, a better rider could have made the turn. And if you do decide to brake, MSF teaches you to straighten up first. So better training would help.

    But, that's not your point. Your point (I think) is that ABS applied in a hard lean corner will still likely result in a crash. I agree. But still, I'll take ABS over no ABS. I have had it kick in on a slick road and other times, and it is very nice to have. But it's not a panacea.

    This guy could have benefited from ABS:

    http://youtu.be/8PE9cozFuAw

    Note how he was not leaned over much at all. In the slow mo, you can see a nice front wheel skid lay down a line of rubber on the road before he goes down. I think ABS would have saved him this crash. Not relevant to this discussion, but that guard rail saved his butt, too, from a long ride down a cliff.
    Rob C. , Raleigh, NC
    '10 R12RT, R90/6
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  8. #8
    Small road corner junkie pffog's Avatar
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    Well not scientific, but in 50k+ miles one of the only times my ABS was not activated on purpose, was leaned WAY over at a track day at Summit Point Shenandoah circuit.

    A quick transition from hard left to hard right at the crest of a hill found another rider blowing his line and heading across my path, just a few feet ahead. I stabbed the brakes, and felt the bars go loose for just a split second, before the abs kicked in, and the front tire regained traction, I of course let off too, but the electrons travel through the bikes system faster than they do mine.

    Yes sudden regaining traction in a slide can cause a high side, but IMHO ABS cycles fast enough to prevent lateral momentum to build, provided there is enough traction to reconnect.

    This is the ONLY time I feel the ABS saved my bacon, and it was on a RACE track. OK purists, have at it. IMHO ABS can save you more that hurt you, any day.

    Besides I can get near maximum braking force NOW, not after I gently squeeze the lever to settle the chassis then adjust the lever pressure to provide threshold force, which for 99.999% of humans is IMPOSSIBLE.

    People that claim practice is as good as ABS, I say bull. Look at ANY professional racing form, car of bike, and you will see the BEST humans at their trade, that get paid millions to do nothing BUT practice, lock up their brakes by mistake. Yes dumb luck might have saved you once, but luck is hard to consistently repeat.

  9. #9
    God? What god? roborider's Avatar
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    Quote Originally Posted by pffog View Post
    IMHO ABS can save you more that hurt you, any day.

    Besides I can get near maximum braking force NOW, not after I gently squeeze the lever to settle the chassis then adjust the lever pressure to provide threshold force, which for 99.999% of humans is IMPOSSIBLE.

    People that claim practice is as good as ABS, I say bull. Look at ANY professional racing form, car of bike, and you will see the BEST humans at their trade, that get paid millions to do nothing BUT practice, lock up their brakes by mistake. Yes dumb luck might have saved you once, but luck is hard to consistently repeat.
    Those 3 statements: ABS is better than no ABS, ABS is better than the average Joe at maximum braking, and even pros make mistakes.

    Those 3 statements really hit home. Sure, I'm all for BETTER ABS, but Andy, is your point ABS is a waste of time or ABS should just be better?
    Rob C. , Raleigh, NC
    '10 R12RT, R90/6
    2007 CBR600RR & 09 V-Star
    Suzuki DR 350

  10. #10
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    To this question, "but Andy, is your point ABS is a waste of time or ABS should just be better?"

    Actually my point is ABS is neither a waste of time (or money), nor should ABS be better. My point has always been to be sure we riders really understand what ABS does, is capable of, and not capable of. I really think a lot of riders have the impression that ABS will always cover thier transgression. Well, ABS "might", but I for one am not willing to depend on it that way. But I would like to see actual test data and video to support my feelings. If I am proved wrong, GREAT! If I am proved right, then no big whoppie on my part, just an understanding would be available to those wanting to know more.

    Years ago I had opportunity to work directly with Bosch ABS engineers at their winter test sites in Baudette MN and in Areplog, Sweden (60 miles from the artic circle). I learned an awful lot about ABS control and principles, enough so that Bosch offerred me a job as a heavy truck ABS engineer (just before the truck market went seriously down, good thing I didn't take the offer).

    I too am an MSF instructor of 20 years, so the control principles are firmly ingrained in the cranium. I also support always using proper technique rather than depending on some support system to save your butt. Good braking skills and cornering skills have FAR higher priority than any ABS system. I looked at that video of the Duc rider lowsiding into the guard rail. For where his front tire locked (note also that his front tire is turned LEFT right as it starts skidding), and that his bike was largely upright, I agree that ABS "could" have helped him avoid the tire skid and lowside. BUT, with that, even far worse could have happened. Again look close at the video and you'll see his front tire turned left, which may be the result of him locking the front wheel. But I suspect, for all his glorious riding gear and beautiful Duc sportbike, that he had a perceptual problem with quick and accurate leaning/turning capability. Hard to say if he TURNED the handlebar left and then clamped on the brake, or if he clamped on the brake and as a result of it locking he turned left on the handlebar. Regardless really, because had ABS helped him regain traction at that instant, and had he kept the wheel turned left, he would have gone quick HARD right, the result of a hard left countersteer! Right into the guard rail. To correct for his initial mistake, after regaining traction, he would then have to press even HARDER LEFT to maintain control and avoid running wide. My bet, ABS or not, this guy was gonna crash. That he lowsided in this instance, I feel, was the BETTER of having ABS help out his ham-fisted over-braking technique. Of course, that's easy to say from behind my laptop. But that his front wheel is turned the wrong way in an area with NO runoff, he's better off he didn't have ABS in my opinion.

    The Duk rider made a decent entry position choice, but then messed up after that. Perhaps freaking out looking at the guard rail and precipice beyond, and then freaked out clamping on the front brake, which he clearly did before attempting quick increased lean-in. For his speed and ground clearance, all he had to do was maintain throttle and press hard on the LEFT handgrip to lean the bike in quickly. He would likely have cleared the turn with NO braking at all. Too bad we don't get to see the broader view of this lowside, to see if oncoming traffic forced his decision. But this particular turn on the MulHolland canyon road gets a LOT of youtube lowside videos. These kinds of youtube videos can be good learning tools, but there is a LOT you have to look at and consider to determine if something like ABS would have saved him. However, again, the perception is that ABS would have saved him, and others might agree thinking it would help them. My gut says in this case it may have been far worse. Far too many variables about ABS control and leaning/turning than we can make here. But always, GOOD BASIC riding skills do make a huge difference all the time.
    Last edited by ANDYVH; 12-16-2011 at 07:20 PM.

  11. #11
    God? What god? roborider's Avatar
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    Ah, I see. I think we pretty much agree on this.

    The Duc rider really did take a corner that was easily makable, and for some reason reacted poorly and dumped it. His skills do not match up with his leather track suit!

    So I agree, TRAINING is #1. Track Day training is to me, a must. If you take corners dragging a knee on the track, you will rarely find you take a corner "too hot" on the street.

    ABS is great to have, and might save a dump, but skill is and always should be #1.
    Rob C. , Raleigh, NC
    '10 R12RT, R90/6
    2007 CBR600RR & 09 V-Star
    Suzuki DR 350

  12. #12
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    In your earlier response, you said you weren't sure if the video was relavent to the discussion. I think it was spot on! This is some canyon racer, on a public highway, in MUCH better riding gear than most of us wear, making a mistake and paying for it. Either his lack of skills, or his poor choice of the skills he had, or that he simply freaked out (my guess) cost him a lot.

    But again, IN THIS INSTANCE, I feel ABS "may" have resulted in a worse outcome. Yet, how may people look at that video and respond likewise, "I feel ABS would have saved him from this crash." What if that rider sued Ducati because they didn't offer ABS on that bike? In court, to an unknowing jury and lawyers, he might get a huge settlement. But with some real study of the video (one of the benefits of this video age), a defense lawyer for Ducati would have closed this one down quick.

  13. #13
    God? What god? roborider's Avatar
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    I meant the comment on the guard rail was not relevant!

    Why do you think ABS might have made it worse?
    Rob C. , Raleigh, NC
    '10 R12RT, R90/6
    2007 CBR600RR & 09 V-Star
    Suzuki DR 350

  14. #14
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    I felt that ABS "could" have made this worse for the following reasons, and again this is based on the conditions we see on the video, and on the premise that the rider, cycle and conditions are all the same:
    1. Look at the conditions preceding the lowside, the front tire is turned to the left.
    2. The bike, once the tire is locked is sliding to the outside of the turn. That's just physics. Once lateral traction is gone, the bike will always slide to the outside of a turn.
    3. Even though the wheel is turned left, at the intiation of the skid, the bike is largely upright. But the front wheel is turned pretty significantly left. That means if traction is suddenly gained, everything above the rotational axis of the bike would have wanted to go to the right, toward the guard rail (high side).
    4. Very marginal to no run-off room. A narrow shoulder, then guard rail, then Wiley Coyote air time.

    Given those conditions, if after initiating the skid, if the front tire would suddenly gain traction I guess some things could happen:
    1. The bike will quickly track RIGHT, not left, due to the aggressive countersteer reaction when the front tire gains traction. If the tire were pointed more straight ahead when lockup initiated, then its simply a straight line stop when the ABS engages and the rider "may" be able to quickly press HARD left grip to redirect the bike into the turn.
    2. But that is IF the rider is quick, skilled, and practiced at QUICK HARD COUNTERSTEERING. This relates to the very little margin for error with no run-off room. The fact that the rider made the massive error of clamping on the front brake instead of pressing into the turn leads me to think he froze up/freaked out, or simply does not have the skills.
    3. So my guess is based on the errors shown, he would not likely have the recovery skills within the very limited space he had to maintain control once traction was gained again.
    4. Given the momentum of the bike at that point, and no run-off room, without a HARD LEFT countersteer, the bike would have quickly run right into the guard rail.

    That could have pitched the rider over the guard rail instead of low-siding into it. Hmm, now that I think about it, once he lost traction and began to fall, its a good thing he DIDNT let off the brake before the bike went down. If he had, the bike could have highsided him over the guard rail.

  15. #15
    Registered User lkchris's Avatar
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    Quote Originally Posted by ANDYVH View Post
    Also, every ABS engineer I have talked to all refer to ABS systems as stability control systems and not as braking systems. They assist stability control by using the brakes.
    And that's tangentially true for cars, although not with the earliest ABS systems.

    Today, using ABS sensors and more sophisticated pumps and plumbing, an individual brake can be activated to maintain stability. It's not necessarily "pumped" either. The parts in common are the wheel speed sensors; ABS will pump brakes if it determines loss of traction; ECS (electronic stability control) will apply individual brakes to maintain straight-line running (steering angle is checked, too).

    It's not really accurate to equate ABS and ESC, but for sure the same wheel speed sensors are utilized and brakes are indeed activated without driver input. There are now systems involving radars that will prevent rear-ending someone and they use servo control of brakes, too, but again these systems are not accurately called ABS either.

    And, it's completely irrelevant to motorcycles, where the only goal is to address wheel lockup. BMW ASC addresses wheel spin by cutting engine power, which can certainly be considered a form of stability control, but brakes aren't involved at all.
    Kent Christensen
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