The Motor Systems

electric bike motor systems

The beating heart of a great electric bicycle is it's drive system. We've compiled this rundown of drive systems that The New Wheel have supported over the years.

Syno-Drive by TDCM

The Stromer ST2 uses an exclusive hub motor developed by TDCM for Stromer that is being marketed as "Syno-Drive." The Syno-Drive hub motor has a number of design changes that make it perform better, weigh less and run smoother than any other drive system we've tried.

The first big design change is that the motor controller for the Syno-Drive hub no longer resides in the motor. Instead, Stromer has integrated the controller into the downtube of the bike. With the controller outside of the motor, Stromer can put more power into the motor, increasing performance and all but eliminating motor overheating. The controller itself is redesigned with Canbus communication and more precise motor controls, a big part of the smoothness of the drive.

The second big change is that the motor now runs at 48V, making the motor both accelerate and regenerate much more efficiently and powerfully. Finally, the fit and finish of the Syno-Drive has been considered from the perspective of service. Instead of a bolt-on axle, the Syno-Drive uses a modern thru-axle for added rigidity and easy removal.

The motor power and data plug has been redesigned for dead simple removal and install: it is now one plug that plugs directly into the motor and can be unplugged by folding up a handle. Lastly, the motor now uses a cassette gear cluster, instead of a freewheel.

TDCM (Hub Motor)

The Stromer ST1 uses a direct drive hub motor (like Bionx) made by the Taiwanese company TDMC. TDCM focuses on both the development and production of electric drive systems for electric bikes as well as for other applications like medical devices, starter systems, and wheelchair to name a few.

The TDCM configuration on the Stromer ST1 is an exclusive design for Stromer. The heart of the system is a direct drive, brushless motor featuring a nominal wattage of 500 watts and a peak torque of 40Nm. The TDCM motor 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 TDCM 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 TDCM hub is extremely reliable - we can attest to that!

Impulse (Mid-Drive)

Derby Cycles, Kalkhoff and Focus's parent company, has been hard at work for the past years optimizing the design of their flagship product: the Impulse motor system. Learning from Impulse 1.0, which was introduced in 2012 and is in active service on over 150,000 ebike around the world, Impulse 2.0 is a next generation drive that offers better performance, quieter operation and some really bright new ideas to make what was already one of the best drive systems on the market even better. In 2015, Derby Cycle's introduced the next iteration of the Impulse system, the Impulse Evo drive.


The Impulse 2.0 motor utilizes a new haul sensor in the motor that enables the motor to put out even better torque than before. In fact, the new Impulse motor can put out a whopping 70Nm of torque, higher than any other mid-drive motor system on the market.


A completely re-designed gear box is at the heart of Impulse 2.0. The new German made gears that combine motor power with pedal power have even tighter tolerances than before, making for near silent operation.


This is the most exciting new feature in our estimation. A small device in the downtube of each new Kalkhoff and Focus bike senses the movement of the shift cable and switches the motor off for half a second. This motor pause allows for easier shifting without the added strain of the motor's power running through the transmission. The shift sensor comes in very handy when paired with an internally geared hub, as the motor pause allows the clutch in the internally geared hub to release and the shift to occur.


The "climb assist" function is really just the ability for us to adjust how long the motor carries on adding power after you've stopped pedaling or slowed your pedaling cadence. Why is this important? Well for someone who has a slow pedaling cadence, we can increase the climb assist so that the motor will continue to assist even when there is a long lag between inputs on the torque sensor. Our ability to tune the climb assist parameter means we can make your ebike fit your style of riding, making for smoother pedal assist for any rider.


The interface for Impulse 2.0 has been completely redesigned. A new thumb controler is backlit for day and night operation. The thumb controller operates the now standard compact LCD display, which displays your battery level, speed, odometer, and trip distance. The new display is mounted to the faceplate of the stem offering great visibility. Premium and speed ebikes will include the redisgned "big LCD" display, which displays all the standard trip computer functions along with estimated battery range, energy savings and a host of customizing options.

Bosch (Mid-Drive)

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.

We've got a whole page dedicated to the Bosch Performance Line electric motor system.

Check it out ›

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.

Xion (Hub Motor)

The 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.

Dapu (Hub Motor)

The 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.

Bafang - 8Fun (Hub Motor)

Bafang (8Fun) is a Chinese manufacturer of electric bike motors. Bafang is one of the worlds largest producers of motor systems, primarily front hub geared motors for the European market (primarily the Netherlands). Besides front hub motors, Bafang also produces a range of rear hub drives, a simple mid-drive motor, and ebike components such as consoles (HMIs) and battery packs.

The Faraday Porteur uses a custom controller similar to the controller in the Stromer ST2, combined with a

250 watt 8Fun geared hub motor in the front hub. Rider input is registered by a FAG bottom bracket torque sensor. On the whole, the system makes for an incredible smooth, responsive ride.

The motor, while geared, is very silent and compact and offers great torque for the size and weight. As with all geared hub motors as compared with direct drive motor, there is more possibility of wear over time due to the added complexity of moving gears inside the motor.

Panasonic (Mid-Drive)

The 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.