How Does Motorcycle ABS Work?

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How Does Motorcycle ABS Work?

On The Road

15 years or so ago, most bikes that had ABS were heavy tourers. Hit a lever hard enough to actuate an older bike’s ABS and you’d be met with a ton of lever pulsing as the system modulated brake pressure a few times a second. You could almost feel the rate at which it could process data. And while that detectable pulsing was able to prevent wheel lock up, it frequently failed to bring the bike to a halt in the same distance a decent rider would have been capable of on his or her own. It could also intervene too soon or in undesirable circumstances.

Jump forward about five years and that pulsing had disappeared, and the stopping distances moved inline with those of a very good rider, but ABS could still trigger where you didn’t want it to, such as while braking over tar snakes. This first modern generation of motorcycle ABS was also confounded by off-road conditions, so most bikes with any sort of dirt pretensions fitted with it came with a big “ABS Off” switch.

Nowadays, the technology has advanced so much that it’s nearly undetectable. You simply come to a controlled, rapid stop in the shortest distance possible. No pulsing, no second-guessing the efficacy, the bike is held at the absolute threshold of grip until you release the lever. Not only is it seamless, but up-to-date ABS delivers all the feel and control you’d get from a non-ABS bike, too. And, it works off-road. Sometimes. On the latest generation of ADV bikes, you can still catch ABS off-guard while attempting to shed speed on a steep descent, where you actually want full front brake lock. But, in general dirt riding, it works pretty well. Learn to ride with it — stop flying down steep descents and leaving braking till the last second — and it will actually add an element of safety. Particularly given the ever-expanding proportions and weights of that class of bikes, it’s a welcome addition.

The level of control and seamless precision of modern ABS even means that on the latest superbikes you can trail brake right up to the limit of a front tire’s grip, relying on the ABS to prevent you from washing the front.

The next generation — represented by Bosch Motorcycle Stability Control now entering production on the KTM 1190 Adventure — sees ABS work to prevent the bike from standing up under braking in turns.

Do You Want It?

Yes. The latest generation of ABS systems removes no control or feel from the rider and even the fastest racers will no longer be able to out-brake the computer, even in perfect conditions. In today’s horrifying traffic conditions, ABS is the last line of defense against careless drivers. On today’s hugely heavy Adventure bikes, it’s tuned to keep you upright even if you take them off-road. With modern ABS, your bike simply stops faster and more safely. That’s an advantage you need, whether you want to admit it or not.

Does your bike have ABS? Why or why not?

Has your experience with ABS been a good one?

  • Bill T

    My next bike must be light weight(sub 400lbs), FI and ABS is standard!

    • John

      Duke 390.

      • yakimushi

        Coming soon… in 2017.

        C’mon KTM. Hurry up and take my money.

        • Stuki

          Note to Big4: The mere mention of light weight and high tech sets off a cascade of replies about some tiny upcomling from Austria……….

          • Piglet2010

            Designed in Austria, built in India.

            • Stuki

              Judging by the engineering prowess of Indian natives I come across out here in Cali; I doubt it will be too long before the opposite is as likely as not. At least if high performance motorcycling ever becomes popular in that overcrowded place.

              • Piglet2010

                Considering how few high-performance motorcycles are sold in the US, it would not be surprising if the Indian market sells more by 2020.

      • appliance5000

        duke 690

        • John

          Good point. The new Yamaha twin would qualify as well.

          I think KTM’s next move should be to twin up that 375 engine to a 750cc model and make that the new middleweight engine.

          • kent_skinner

            That would be awesome.
            A good friend of mine has a Duke 690, and lives where having a single isn’t a penalty. I have to do enough freeway time that I don’t want a single. However, a 750 twin that only weighs a bit more than a 690? Mmmmmm. Yeah.

  • octodad

    a rider told me his $16k Ducati had ABS and he loved it, got ABS w/ my new Honda and it makes me feel more safe. I can jam on the binders w/o skidding and stop on a dime.

  • ThinkingInImages

    I have a 2013 Honda CBR205R, ABS model. It’s my first motorcycle with ABS (and linked brakes, rear caliper to one out of three pistons on the front caliper). It’s brilliant. It only took one near miss to convince me it should be standard on every motorcycle. ABS redefines “performance” by improving it.

    • John

      Wow, that’s a super rare bike, take care of it.

      • ThinkingInImages

        Around here it is – it’s the all black model. I’ve never seen another.

        • Jeka

          He meant the 205 CC. :P

          • ThinkingInImages

            Fixed it. That’s what I get for typing fast when the dog wants to go out.

  • John

    I hope these work better than my Dakota’s, because when the Dakota ABS kicks in, it’s almost like hitting the accelerator. It’s like “hey, I’m kinda slowing down…wait, WTF just happened?!?” And then you have to change your underwear.

    • Jai S.

      My experience is you feel pulsing through the levers, and you feel a very slight loss of stopping for what appears to be fractions of a second. The overall effect is much better braking than locking up, manually releasing and re-applying of the brakes.

    • runnermatt

      I had a 95 Ram 2500 that did the same thing. It comes from worn or out of adjustment rear brake shoes. Don’t buy the cheap replaco shoes get the (likely) Bendix rear shoes. The cheap ones cause the rears to lock and unlock as the abs cycles.

      I can confirm how scary it can be. I started to put that truck off-road a few times in order to avoid the potential accident under panic braking. It also takes a lot of self control to take your foot off the brakes and reapply them more smoothly to avoid activating ABS again, all while hard to pa ic braking.

  • Ben Mcghie

    Do any of the top race classes use ABS? I know MotoGP uses traction control… what about the other classes, and what about ABS? Seems like that is flat out cheating.

    • http://RideApart.com/ Wes Siler

      It’s banned.

      • Ben Mcghie

        Excellent. “Last of the late brakers” remains a prestigious honorific.

      • Stuki

        But TC is not? Wonder who that made sense to.

        • http://RideApart.com/ Wes Siler

          They found it too hard to stamp out, teams were baking it into ECUs under layers of other programming and whatnot. With it banned, rich teams were able to hide it and poor teams were left in the cold. With it legal, the playing feel is a little more level.

          • Stuki

            Interesting. Never thought about it that way. I guess you can embed all manners of sensors, gyros and whatnot right on chip these days.

            Are there any high profile racing series where ABS is allowed? Thinking of racing as a test bed for street riding tech, it would make sense to allow it in at least some more ostensibly street relevant series; like Superbike. But perhaps the racing gets so dull and boring that noone would pay any attention, if both braking and throttle management were taken out of the equation.

          • Stuki

            On another note; is TC on showroom bikes so good now, that even top riders are faster around track with it than without? A few years ago, I remember some magazine did a test, and their fast but not alien testers were all faster with TC off, although, if I remember correctly, on the Aprilia RSV, the difference was fairly small.

            On infinite HP MotoGP bikes, with infinite budgets for TC calibration to each track and rider, TC is obviously beneficial, but are there still riders out there that cold take the latest Panigale or HP4 around a track faster with TC off than with it on, even in the least restrictive “race” mode?

  • Jack Meoph

    I haven’t had the ABS engage on my new Ducati Monster yet. First bike I’ve had with ABS. I probably should force it just to see what it’s like, but when I get on the bike, I just don’t think about it.

    • Paul Stevens

      You don’t think about it at all. TC and ABS just sit in the background and kick in when my ambition overrides my talent, or when road surfaces chuck in a wildcard. But by all means, take her out one day and just grab a handful of lever. What’s the worst that can happen? :P

      • Stuki

        The new 1190 adventure even has a system with logic to take lean angle into account. I saw some magazine testing it by being told to just grab a handful while leaned over; on cobblestone! Talk about life saver if coming around a corner in the rain, only to see a family of deer blocking the road.

  • Paul Stevens

    I have a 2014 BMW S1000RR, which I commute on. Heading down the last stretch of road before my office park one morning, I watched a car entering a traffic circle ahead of me, which my brain found so interesting it forgot to inform my fingers to apply some cautionary pressure to the brake lever. By the time the lump of sludge between my ears had cottoned onto the fact that using a slab sided SUV as a stopping aid was a bad idea, it was time to hold onto the front lever for all I was worth. As someone who has taken a trip over the bars of his GSX-R1000K5 thanks to a pedestrian who figured that five meters was more than sufficient for me to bring myself and my bike to a halt in order to protect his dental work and my fairings, the net result of piling on the anchors on an ABS equipped bike was awesome. I felt a slight pulse through the lever, but lost nothing from the steering, and escaped the situation with nothing more than annoyed look from Mrs SUV Driver, my bike and person completely intact. Of course, I’m delighted that in South Africa we’re allowed to wear mirror tint visors, which prevents motorists from seeing the stupid look on my face when stuff like this happens on two wheels.

  • Avboden

    Thanks, BMW :-)

  • KeithB

    Usually when ABS is mentioned, someone will say”well if you learn to ride, you don’t need it”
    Riiiiiight….
    I have been riding a long, long time and while I have practiced hard braking, I am very aware that my skill level isn’t as good as someone who is on a track or carving canyons regularly. All of my bikes up until the FJR did not have ABS. Never crashed but I’m very happy to have ABS on my new bike in case of that WTF!!! situation.
    After all, I am getting older…

    • ThinkingInImages

      Same sentiments here. I see ABS as part of the performance package, just like FI. If my motorcycle had traction control and modes, and active suspension, I’d see those the same way. Performance is not just about horsepower, torque, acceleration and top speed. That’s about the machine. ABS, and all the new tech, is about the rider getting the most out of the machine. It makes it all accessible.

  • Adam

    So if riders are interested in ABS and willing to pay $500 or more for it why isnt it available as an option for more bikes?

    • Justin McClintock

      I think it will be eventually. Remember, we’re still climbing out of an economic hole. Plenty of bikes haven’t been redesigned since the 2005-2007 period when ABS on a bike was pretty rare. Once they are, chances are ABS will be an option on far more models.

      • Stuki

        It’s only fairly recently that cost effective abs systems got god enough to not be in the way during high performance driving on tracks and in canyons. The old BMW systems were flat out scary to riders who intentionally pushed their bikes close to their tires traction limits; as the brakes seemed to be in possession of a distinctly slow witted mind of their own.

        But with the latest systems, I can’t imagine anyone not on payroll to race consistently out riding them on tarmac, even on a smooth, dry, well known track. Dirt and Supermoto may still be a bit different, although strides are being made even there.

        • Justin McClintock

          I know I certainly wouldn’t mind my DRZSM having ABS as I’ve gone down on it after locking the front wheel (due in no small part to the stock tires being HORRIBLE). That said, it would need to be defeatable for offroad use. But an off switch isn’t all that complicated to add.

          • Stuki

            ABS able to outbrake top riders under SuMo conditions, is pretty close to the holy grail of brake tech. Algos able to discern exactly how large a slip angle to allow during backing in…….. For street use, ABS is definitely a boon on motard type bikes, though.

      • Piglet2010

        At least around here, it is very hard to find a “metric” bike with ABS, if it is also available without – the dealers seem to think non-ABS bikes sell better.

        Wonder if the manufacturers will ever make ABS retrofit kits? I would buy one for my Bonnie, if reasonably priced.

        • Stuki

          Retrofits would make all the sense in the world. Lawyers will tell you, and anyone they get asked for advice regarding whether or not to invest in you, to stay the heck away from something as lawsuit prone as MC brakes, however. Such is life in our overlawyered dystopia. Better have people die on the streets than lawyers losing an opportunity to insert themselves into value chains created by others.

  • http://metabomber.com/ Jesse

    How does ABS work? Magic braking elves.

    • stever

      Alchemical Braking Sprites

      • http://metabomber.com/ Jesse

        I bow to your superior comedic style.

        • stever

          thesaurus jokes

  • Strafer

    “By comparing wheel speeds and the rate of change for each”
    aha!

  • markbvt

    The ABS on my Tiger 800 XC is so good, and so nonintrusive, that I long ago stopped bothering to turn it off while riding offroad. And I’m convinced it’s saved me several times from crashes due to front-end lockups when I had to brake hard on wet/slippery surfaces. It’s turned me into a believer. My future bikes will have ABS too.

  • http://www.nathanielsalzman.com/ Nathaniel Salzman

    It’s worth noting that you’ll still get shorter stopping distance with properly applied (which is to say, smoothly applied) brakes than you will with ABS, simply because you’re giving the suspension time to compress and the front tire time to flatten out, but having ABS is still a great way to keep you from over-braking. My Triumph Tiger 1050 is my first bike with ABS and it’s fantastic. I still practice proper braking technique so that I’ve got good habits, but It’s really good to know that if I do need to brake hard, I have that safety net to help basically eliminate the limit. In terms of feeling it, I find myself getting into the ABS on my rear wheel much more often than front. It’s a strange feeling to feel the pedal go limp for a brief instant then come back, but it’s also good feedback that I’m at the limit of traction on that wheel.

    • Stuki

      If i is still true that you can get shorter stops manually than with the latest abs, then that is only because of lack of refinement of the abs systems. There is nothing inherent in properly calibrated abs making it stop worse under any circumstance than brakes sans them. Calibrating engagement for “the average user”, MAY create situations where an expert could stop faster, simply because there are situations (loose sand) where riding a locked wheel, if one can do it without falling, is preferable to not locking it up. But that is really a calibration issue; not a knock against abs itself.

      • http://www.nathanielsalzman.com/ Nathaniel Salzman

        I’m not knocking ABS either, but the presence of an ABS system is only one factor in braking effectiveness. It’s simple physics. If I ease into the brakes smoothly and then apply them fully (which is what I mean by “proper braking technique”), then I’m giving the suspension a chance to plant the front wheel and the front tire a chance to spread and increase the size of my tire contact patch before the full force of braking is brought to bear. This means more grip to work with, no matter what braking system I have. That means more stopping power and the tire is actually less likely to lock up in the first place. I’ve effectively grown the performance envelope of my brakes by applying them properly. My actual limit of grip is greater because I have more grip to work with, so if my ABS does kick in, it’s actually under a greater braking force and more of my speed will have been arrested before the system kicks in and starts shedding brake force to keep me upright. For every few milliseconds that the brakes have to modulate (that is, to let up) in order to contend with the premature lock-up that I’ve induced by simply grabbing the front lever, that’s braking power that’s wasted in trying to stop the bike. That translates into feet added to my overall stopping distance.

        ABS is terrific, but how you apply your brakes still matters and you’ll still have shorter stopping distances with good technique than you ever will just grabbing the lever and relying on the system alone.

        • Justin McClintock

          You can use those same braking techniques on a bike WITH ABS though. No reason why no. And ABS will be hands down better than any person can about straddling the line of maximum braking vs. locked wheel. Obviously the physics of a motorcycle are slightly different than that of a car, but one can easily point to the advent GOOD ABS braking systems in cars and the increasing stopping performance that came with them. The Dodge Viper was a perfect example as it was one of the last high performance cars to come with ABS. Once they finally added it, the best stops it produced from 60-0 were several feet better with Joe Blow behind the wheel than they were with even the best professional racers in non-ABS cars (even though the rest of the braking systems were still effectively the same).

          Simply put, a well developed ABS system can out-brake any human. Period.

          • http://www.nathanielsalzman.com/ Nathaniel Salzman

            “You can use those same braking techniques on a bike WITH ABS though. No reason why no.”

            That’s what I’m saying. ABS is great, and it’s even better when you practice good braking technique.

            • Justin McClintock

              Gotcha, and yes, totally agree. The best use of ABS is not having to use it.

              • http://www.nathanielsalzman.com/ Nathaniel Salzman

                Exactly. I’ve got ABS on my touring bike (Tiger 1050) and every bike that replaces it will have ABS as well.

          • KeithB

            The inline braking performance is only one aspect of ABS.
            Something that gets overlooked is the idea of being able to brake hard AND steer the vehicle.
            That is where ABS really has the best “accident avoidance” benefit, at least in cars and trucks.
            The motorcycle application of “lean and brake” ABS is still being perfected.

        • Stuki

          The optimum rate of easing into the brakes and compressing the suspension, which varies by surface and other factors, is, at the limit, better discerned by specialized hardware and algorithms, than by rule of thumb experience and judgement. You’re probably right that as a good rider, you may still be able beat abs by refraining from complete ham handedness, but not for long.

          • http://www.nathanielsalzman.com/ Nathaniel Salzman

            Except ABS systems aren’t designed to modulate how aggressively you’ve pulled the lever — only to keep the wheel from locking up.

            Here’s the thing, I’m not at all saying that ABS isn’t great and doesn’t make bikes safer. It totally does. All I’m saying is don’t pretend that good technique is no longer important because you’ve got ABS on your bike.

            • Stuki

              For minimal braking distance, you want to be at the lockup threshold ALL the time. From the instant you decide to brake, until the bike is stopped. The rate of deceleration will be lower prior to max contact patch loading, but you still want to slow down as much as you can even before you have the benefit of the suspension fully compressing and the contact patch fully spreading. Well designed ABS can do this better than any human powered heuristic; at least on pavement.

              IF your abs system is good enough, as in equivalent to where it currently is on cars, the procedure for achieving the shortest stops cease to be one involving split second judgment regarding suspension loading and weight transfer. All you do is send a clear signal to the controller that you want to stop as quickly as possible, and the controller takes it from there. With consistently shorter stops than even Marquez could achieve.

              Cars nowadays are at a level where they can apply max braking power faster than the contractile speed of human muscle tissue can fully compress a brake pedal; by relying on rate of dipping in to determine a panic brake is in progress and mechanically slamming on the brakes. Bikes do not currently do this; but they will. With ever more sophisticated sensors, controllers capable of processing ever more data, and ever more experience with the kind of algorithms required to achieve minimal stops under varying conditions; pretty much guarantee that in not too long even the aliens racing MotoGP cannot outdo the robots.

              • Piglet2010

                In a car, this brake assist will merely move the driver up against a tensioned seat-belt. On a motorcycle, it could toss a rider over the bars, even with a system that prevents stoppies.

                • Stuki

                  Unless you’re riding a uniquely long and low bike, equipped with lower bars and something substantially grippier than the bicycle tires most of those come equipped with these days, that’s highly unlikely.

                • Piglet2010

                  Most endos on push bikes are due to the rider not properly bracing his/herself, and not the bike going over with the rider on it. And this is with a 23mm wide tire and a caliper brake that is only slightly more powerful than the front brake on a 1960′s Sportster.

                • Stuki

                  Would probably be the case on motorcycles too, if riders rode around by standing on the seat……… :)

        • KeithB

          “how you apply your brakes still matters’

          Good point.
          ABS is not a replacement for bad braking technique.