Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126944
The rider on the left shows what it's like to stop with the BMW ABS system while the rider on the right without ABS uses the outrigger. BMW Anti-Lock Brake System A faster way to slowdown By Paul Van Zuyle As every movie producer knows', the best way to get someone's attention is with a good crash. So when BMW of North America president Gary Cooper came to' Anaheim, California in December to introduce his company's antilock brake system (ABS), he took his cue from Hollywood, and crashed a motorcycle to prove the value of the new German innovation, Of course, just like in the movies, nobody really got hurt, since the crashing was done on an outriggerequipped BMW KIOORT that merely fell onto one of its "training wheels" when the brakes were locked. Each time former Formula Two road race champ David Emde sped into the hosed-down parking lot, slammed on the brakes and tipped over. the corps of journalists watching winced with the collective memory of many similar crashes. Then,currentFormulaTwochamp Don Greene roared into the same parking lot on a KIOORT with the ABS system, jumped on the brakes, and slowed to an uneventful stop. But underneath him, the wheels of, the ABS-equipped BMW gyrated in a vivid dance, stopping and starting over and over again as the system pumped the brakes. The demonstration was repeated over an alternating surface of sand and wet asphal t with the same graphic results. The implication had been made perfectly clear: ABS removes one of the major hazards to motorcyclists in panic-stop braking, particularly on wet or slippery pavement. BMW emphasizes, though, that ABS is not a cure-all for riding too fast. For one thing, the company says that unlike automotive ABS, the motorcycle system does not work in corners. The reason, say BMW engineers, is that a motorcycle subjected to maximum braking while leaned over will tend' to stand up straight, and the rider will lose directional control. And on dry pavement, ABS offers little advantage in stopping distance for a ski lied rider. Where ABS really shines, however, is on variable surfaces, like patches of sand and oil. There. BMW says that ABS operates far fasler than human reflexes, and can o((er up to a 50% reduction in stopping distances compared to those obtained by a skilled rider operating conventional brakes. BMW first began experimenting with anti-lock brake systems for motorcycles in 1978, the same year that the company introduced ABSon stan- dard production cars, The testbed motorcycle was an RIOORS. At first, BMW tried to adapt their' automotive system to the motorcycle, but there we.re several problems with that approach. One was that the automotive system was large and heavy, and would simply be difficult for a motorcycle to carry. The car system was also designed to use much more brake fluid than a motorcycle does, so the standard Brembo brakes that BMW uses would have had to be altered. . Perhaps'the biggest problem was the pulsations that automotive ABS sends back to the brake lever when it is working. BMW reports that test riders found the sensation anywhere from irritating to barely tolerable. So BMW began looking for a new system that would be applicable to motorcycles. The company says that for several years they examined a British hydromechanical system as it was being developed. but they ultimately focused their attention on an electromechanical system made by the German firm FAG KugeUischer. The BMW/Kugelfischer system senses wheel speed with an elec.tronic The electronic control unit sits under the seat; perhaps the biggest diudvantage of the ABS system is its price. BMW expects to offer ABS as an option for its K100 RS, RT and IT next fall for approximately .1000.