When every tenth of a second counts.

Triathlon and time trial racing are gaining more and more fans every day. Technological innovations, such as the electronic drivetrain, are highly sought-after components when every second counts on the way to the finish line. The EPS (electronic power shift) system, of bicycle component manufacturer Campagnolo, took many years to develop. DC motors from maxon, are responsible for executing the shifting processes within tenths of a second.

3282 kilometers in three weeks – that is the challenge of the Vuelta a España, one of the three “Grand Tours” in cycling and, after the Tour de France and the Giro d’Italia, the most important stage race in the world. Winner Alberto Contador (STB) was followed across the finish line by fellow Spaniard Alejandro Valverde, of Team Movistar. This success was achieved using the Campagnolo electronic drivetrain.

The Italian company started developing the electronic drivetrain in 1992. The history of Campagnolo's electronic drivetrain, which today is called Campagnolo EPS (Electronic Power Shift) went through six planning phases, each resulted in important innovations, direction changes and great challenges. The cooperation with maxon commenced in 1994. Three years later, the first solution for a shift mechanism using a maxon was born. After several redesigns, as well as modifications to the bicycle itself, the engineers from the Campagnolo Campy Tech Lab™ developed a completely new design for the shifting group, the main reason being the switch from a 10-speed to an 11-speed system.

In November 2011, the EPS Electronic Power Shift was successfully introduced to the market. This system consists of a rechargeable battery, electronics, shift lever, wiring and drive mechanism. The maxon motors are used at the rear shift mechanism (see video 1) and at the front derailleur (see video 2). The derailleur was completely redesigned to make it suitable for modern frames. The motors were adapted as well. To achieve the required maximum precision with minimum tolerances, the focus was placed on miniaturising the rear derailleur and finetuning the electronic calibration. With the electronic shift system, a very high shifting accuracy, a high speed of response and the required power are achieved. This makes faster shifting possible and the position of the derailleur can be adjusted with higher accuracy than is the case with a mechanical system. Switching from the smallest to the largest sprocket requires just a single click at the shift lever. To be more precise: The electronic shift mechanism can shift through eleven gears in only 1.5 seconds.

High-precision maxon motors for accurate shifting
The motors are the core of the shift system – they move the derailleur and the shift mechanism of the racing bicycle. The brushed maxon DC motors had to be small and strong enough to provide peak power. For the EPS electronic shift system, customised DC motors, from the RE family, and gearheads are used. For the shift mechanism (at the rear), a motor with a single-stage, integrated gearhead is used. “The maxon technology offers solutions that easily withstand the extreme ambient conditions encountered on racing bikes and, in combination with the extremely good performance of the small RE motors, the electronic shift system is unique on the market,” explains Marco Campagna, Group Product & Marketing Manager at Campagnolo. Only nine months after the introduction of the electronic Super Record EPS and Record EPS drivetrain systems, Campagnolo has already presented the Athena EPS drivetrain. It features the same functions, but the components are largely made of aluminum.

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