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ABS for pedelecs

Bosch’s E-Bike anti-lock brake system (ABS) for pedelecs uses CAN for communication. The ABS improves the riding stability and steerability of the E-Bike – especially under slippery road conditions.

(Photo: Bosch)

Bosch, producer of motorbike safety systems, is about to launch the E-Bike ABS series-produced anti-lock braking system. Due to this development it is possible to prevent the pedelec’s front wheel from locking up and also to limit the lifting of the rear wheel – due to a system. In this way the braking distance can be shortened and the risk of falling over the handlebars is reduced. According to a study carried out by Bosch's Accident Research Division, pedelec accidents could be reduced by as much as 25 percent if all bikes were equipped with the ABS system. The system will be available from Autumn 2017 onwards – initially for selected fleet partners. Series production for trekking and city E-Bikes provided with the Bosch drive system is planned for Autumn 2018. The ABS unit uses communicates with the drive unit and other devices by means of CAN.

Bosch is launching an anti-lock braking system for pedelecs (Photo: Bosch)

Every year more and more people are opting for the pedelec. In Germany, roughly three million cyclists are currently using electric assistance. As Claus Fleischer, CEO of Bosch E-Bike Systems, explained: "In order to establish this modern form of mobility for the longer term, safety is a pivotal factor for E-Bikers and their environment." Two studies undertaken by Bosch Accident Research indicate that the accident rate can be reduced if the pedelec is equipped with an antilock braking system.

Bosch studies

In the first study, researchers examined more than 500 bicycle accidents in Germany. Their main finding: With the correct braking behavior, many accidents can be avoided – or their consequences alleviated. They found that in 20 percent of cycling accidents the rider had fallen before the actual collision occurred. Many of these falls were the result of an incorrect braking response (or a failure to June 2017 brake). ABS ensures more stable and more effectively controlled braking when critical situations arise.

The ABS prevents the front wheel from locking up and the rear wheel from lifting off the ground (Photo: Bosch)

The second study, based on data from more than 5 400 bicycle collisions and falls, also confirms that no braking took place in up to 75 percent of collisions. This is where ABS systems can be invaluable. According to the accident researchers, almost a quarter of pedelec accidents could be avoided through the use of ABS. Moreover, the number of accidents with severe injuries could be reduced further, they found. Fleischer is convinced that "the introduction of a system of this type can improve road safety in the longer term." Braking systems optimize braking behavior and reduce braking distances. The Bosch ABS combines front-wheel ABS with a rear wheel lift-off regulator, thus increasing safety substantially. By regulating the braking pressure of the front brake during critical braking maneuvers, the situation for the biker is stabilized and the risk of falling off is significantly reduced.

Fleischer added: "With front-wheel ABS, wheel speed sensors monitor the speed of both wheels. As soon as the front wheel threatens to lock up, for example in the event of a brake application which is too strong, the E-Bike ABS regulates the braking pressure and thus optimizes the stability and maneuverability of the E-Bike." This is a decisive advantage, especially on slippery road surfaces or on loose, wet terrain as it means that the pedelec can be slowed down carefully and brought to a standstill.

The ABS will be in use with bike fleet partners in 2017 with the Performance Line Cruise and Speed, in combination with the Intuvia display (Photo: Bosch)

The rear wheel lift-off regulator in the ABS unit ensures that the rear wheel stays on the ground in the event of extreme overbraking, especially on a surface with good grip or on descents. Wheel speed sensors detect when the rear wheel is lifting and adjusts the application of the front-wheel brake. Fleischer: "The Bosch E-Bike ABS reduces the braking force at the front wheel briefly, with the result that the rear wheel quickly regains contact with the ground. This lessens the probability that the e-biker will fall head-first."

Development and technological partnerships

Anti-locking devices for two-wheelers were first installed by Bosch in a police motorbike in Japan in 1994. Since 2007 the Bosch Development Centre for Bicycle Safety in Japan has been responsible for the systems. Bosch E-Bike Systems has been able to use elements of the motorbike ABS in the E-Bike ABS – specially adapted to suit the riding and braking habits of pedelec users. The company's partner for the development of brake technologies is Gustav Magenwirth (Magura). The ABS unit will be launched with the CMe-ABS, which has been developed by Magura.

Initially the ABS will be installed only on trekking and city bikes with 28-inch rims. The E-Bikes for fleets are equipped with the Performance Line (Cruise and Speed) combined with Bosch’s Intuvia display.


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