The New Wheel
Bionx electric bicycle motor cutout
The Electric Motor Systems

Panasonic (Mid-Drive)

panasonic-mid-drive-motor.jpgThe Panasonic mid-drive motor is a remarkable bit of engineering. The basic motor design has stayed the same since the early 90s when Yamaha and Panasonic began building drive systems for pedal assist electric bicycles. What has changed dramatically is the battery technology, which has allowed the Panasonic drive, which since the beginning was extremely reliable, to get better and better, offering riders more power and better range per charge. Today Panasonic remains a top-tier electric bicycle drive manufacturer being spec'd on a wide range of bikes from companies such as Kalkhoff, Focus, Raleigh, KTM, Helkama, and BH Easy Emotion.

What makes Panasonic the benchmark in the industry for performance and reliability is an initial, consequential design decision: the middle motor. By placing the motor in the middle, the motor is able to gain the mechanical advantage of the gears on the bike, which amplifies the power of a small motor and allows it to efficiently power a rider up any hill. The placement of the motor in the middle also allows for simpler servicing—as the motor is one unit that can be easily removed—as well as keeping most of the rest of the components standard, another benefit for service. 

Bikes with Panasonic: We no longer stock bikes with the Panasonic drive.

Impulse 2.0 (Mid-Drive)


Update: We've writen a complete description of Impulse 2.0, the newest version of the Impulse drive. Read all about it.

The Impulse motor is a mid-drive motor made in Germany. It was developed as a partnership between Derby Cycle Werke and Daum Electronics out of Fürth, Bavaria, a large electronic fitness equipment manufacturer. In 2011, Derby Cycle Werke took a 50% interest in Daum and licensed the Daum motor system under the Impulse name. Beginning in 2011, the Impulse system took its place in the motor line-up of Derby Cycle Werke's brands which include Kalkhoff, Focus, Gazelle, and Raleigh in the German speaking world. 

The Impulse drive is unique for many reasons. First and foremost, it is a middle motor, with all the benefits outlined in the Panasonic article above. An added benefit of Impulse is that it is capable of putting out up to 80 Nm of torque through the drivetrain, making it the strongest hill climber in our line-up. The power is delivered through a single chainring—as opposed to a seperate motor sprocket as on the Panasonic drive—which allows for higher torque and less drivetrain complication. On a similar note, the Impulse is a direct drive system, meaning there is no planetary gear that the motor works through. This allows for much higher efficiency and simplicity of design. Lastly, the Impulse motor's pedal assist takes into account torque, speed, and cadence to give more nuanced and accurate pedal assistance. Take a test ride and you'll see what all of these improvements add up to. 

Bikes with Impulse: Kalkhoff Sahel i8 CompactKalkhoff Sahel i8, Kalkhoff Sahel Light i8, Kalkhoff Agattu i8

Bosch (Mid-Drive)

Bosch-mid-motor-ebike-system.jpgUpdate: We've got a whole page dedicated to the Bosch Performance Line electric motor system. Check it out.

The Bosch mid-drive motor system has quickly become the leading motor system in Europe since its debut at Eurobike in 2010. Bosch's quick success can be chalked up to many things, but perhaps most important has been its renowned reliability and performance. By building on the middle motor pioneered by Panasonic in the mid-90's, Bosch started with an efficient and reliable design. But Bosch improved upon what Panasonic had been doing in important ways: adding more sensors - torque, cadence, and speed - a single chainring design like Impulse, for better reliability, and designing an advanced console for better control.

At Eurobike 2013 Bosch introduced a brand new drive with a number of key improvements including lighter weight, smaller footprint, a direct drive design (like Impulse) and more torque. This new motor design eschews the standard chainring of earlier versions for a small motor sprocket that offers more power. Most importantly, Bosch will support it's new performance series motor in North America beginning in early to mid 2014.

Bikes with Bosch: Felt SPORTe, Felt NINEe. Read our take on the Bosch drive

Bionx (Hub Motor)

The Bionx motor system is a direct drive hub motor assembled in Aurora, Canada outside of Toronto. Bionx is connected with Magna International, the largest car parts manufacturer in North America, and has its headquarters at Magna's campus. 

There are a number of things that make Bionx unique. Bionx pioneered the introduction of torque-sensed pedal assistance by creating a drive system with a torque sensor and controller integrated into the motor. This allowed for clean and easy installation, minimized reliability issues that result from faulty wiring, and simplified servicing. In 2010, under Magna's direction, the sophisticated CanBus communication system was built into each motor, allowing for updates to firmware, more precise motor and battery control, and computer monitoring.

Bionx is the perfect system for moderate to steep hill climbing and instant acceleration. Bionx's regenerative mode is unique in both its efficiency (up to 15%) and its usefulness—it will automatically slow your bike down when the brake is applied lightly, saving your brake pads and extending riding range per battery charge. Finally, the direct drive motor design allows for extremely reliable performance—the two bearings in the motor are the only wear points—and completely silent operation.

Bikes with Bionx: Xtracycle Edgerunner Electric BikeBionx Urban Conversion KitBionx Cargo Conversion KitBionx Sport Conversion Kit


Xion (Hub Motor)

Kalkhoff and Focus Xion Electric Bike Hub MotorThe Xion motor is a new drive system available on Focus and Kalkhoff electric bicycles. The drive was developed in cooperation between Derby Cycles, the parent company of Focus and  Kalkhoff, and Alder, a German based wheelchair motor manufacturer. The Xion drive is a traditional, reliable direct drive hub motor with a twist: it uses a sophisticated optical sensor to precisely know the position of the copper windings relative to the magnets and apply power in exactly the right place at exactly the right time. This allows the Xion drive to work at an extremely high efficiency (up to around 80%), doing more with less wattage, and thus not heating up too quickly while giving plenty of torque. In fact, in our testing of the new drive we’ve found it to be on par with a mid-drive motor system in terms of giving consistent torque on extremely steep hills. Other benefits of the Xion drive include a sophisticated control panel, regenerative brake assist, a quick release rear hub, and one of the most smooth performing torque sensors on the market. 

Bikes with Xion: Kalkhoff Pro Connect X27Focus Jarifa Offroad Premium, Focus Aventura X30

Dapu (Hub Motor)

geared-hub-motor.jpgThe Dapu geared hub motor is made by a Japanese company in Shanghai, China. The Dapu motor is a geared hub motor. This motor type is distinct from a direct drive motor like Bionx, and has a variety of benefits stemming from its design that can be appreciated in its unique ride feel and performance. Geared hub motors work by transmitting power from a high RPM motor to the slower RPM wheel through a system of planetary gears. Because of the physics of electric motors, this "gearing" allows for higher torque and efficiency from the motor. Thus, the ride feel of a BH Neo bike is extremely sporty with consistent torque, even up very steep hills. The only two drawbacks of a geared motor is a higher possibility of ware due to more moving parts, and a higher noise level than a direct drive motor. But we believe the benefits far outweigh the drawbacks and make the BH Neo bikes a highly compelling option. 

The Dapu motor does not have a torque sensor or controller built into it. Thus, on a bike like the BH Neo, the torque sensor is designed into the rear dropout, and the controller is attached to the frame behind the battery.

Bikes with Dapu: BH Neo CrossBH Neo Jet, BH Evo Eco Lite

ultra motor (Hub Motor)

Ultra Motor Electric Bike Motor on StromerThe Stromer ST1 uses a direct drive hub motor (like Bionx) made by the Taiwanese company Ultra Motor. Ultra Motor Taiwan should not be confused with the former company Ultra Motor that developed the A2B electric bike: they are distinct companies that were seperated in 2011 through a bancruptcy filing of the parent company. Today Ultra Motor Taiwan focuses exclusively on the development of electric drive systems, while the former electric bicycle development arm that built the A2B was sold to the Indian scooter manufacturer Hero Motor Corp.

The Ultra Motor configuration on the Stromer ST1 is an exclusive design for Stromer. The heart of the system is a direct drive, brushless motor from Ultra Motor featuring a nominal wattage of 500 watts and a peak torque of 40Nm. The Ultra Motor hub is a large motor that while heavier than other motors such as Bionx, benefits from less sensitivity to heat buildup when climbing or regenerating.

Like the Dapu motor used on BH Easy Motion bikes, the Ultra Motor drive does not have a torque sensor built into it. Stromer uses a TMM4 torque sensor built into the rear dropout. Unlike the Dapu motor however, the Ultra Motor hub does have a specially configured controller built into the hub. The benefit of an integrated controller is easy troubleshooting, while the drawback is inability to service a bad controller as well as a lower heat tolerance for the motor as a whole. The good news is that after many years of development, the Ultra Motor hub is extremely reliable - we can attest to that! 

Bikes with the Ultra Motor Drive: Stromer ST1 Elite, Stromer ST1 Platinum.

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