Chainless Digital Drive Ebikes, a Promising Evolution?

A new breed of ebikes is coming, which generate electric power through pedalling. The advantages are considerable.

They are already for sale. The concept is simple: instead of conveying your pedal power to the rear hub via a chain or a belt, you action an electric generator with your pedals. The electric energy thus produced feeds a conventional rear hub ebike motor, or the ebike battery.

The advantages of digital drive ebikes

• outstanding for e-cargo bikes
• very performant for urban riding
• much reduced maintenance
• ideal for deliveries, fleets and rentals
• smoother and easier pedalling
• elimination of expensive wearing parts
• reduced production costs
• more suitable for bad weather

A simply logical technology

Transforming mechanical energy into electrical energy which is again turned into mechanical energy is probably the most common process in our society. Every time we turn on one of the many electric motors at home, we use the mechanical energy of a wind or steam propelled turbine, which produces the electric energy that becomes again the mechanical energy of our electric device.

Even a big car manufacturer has adopted the same technology

Nissan is now offering its two best-selling models, the Qashqai and the X-trail, equipped with such a technology: a gasoline motor propels a generator which produces the electric energy that an electric motor turns into mechanical energy for the wheels.

The results are quite impressive especially for urban driving, whereby Nissan declares a very efficient mileage, 16.9 kilometers per liter. On the motorway, only 13. 5 km per liter, since there is much less braking regeneration.

The multiple pros of chainless digital drive ebikes

There are no chains nor sprockets, no cassettes, no chain rings. In the end, the most wearable parts of the ebike are eliminated. This is particularly beneficial for ebike rentals, cargo ebike fleets, and even daily commuting to work, since maintenance is drastically reduced.

• Pedalling cadence can be much more uniform and regular.
• The electrical generator can even detect any differences of muscle power in your legs. For example, if your left leg is slightly less strong, it can make it easier pushing the left crank.
• Pedalling would be more efficient, since the human body performs better when the level of muscular effort is constant and uniform.
• Digital drive ebikes should be better in poor weather conditions, given the absence of mechanical drive parts like chains, etc.
• Digital drive ebikes can more easily use regenerative braking, what makes them particularly performant when stops are frequent, like during city commuting and deliveries.
• They can be particularly useful for physical reeducation, since you can alleviate the load required by pedalling, no matter how hilly is your path.
• Ebike design would enjoy new possibilities, such as more easily conceiving foldable ebikes, given the absence of chains and a simpler, leaner bike structure.
• Ebike production costs should be reduced, thanks to less driving parts, especially in the medium term, when scale economies will kick in.

The disadvantages of chainless digital drive ebikes

The greatest disadvantage is that whenever you convert energy, like electric energy into mechanical energy and vice versa, there is a loss. When you instead apply the mechanical energy of your legs to your pedals, which in turn delivers it to the rear wheel, there’s only a small loss. If that same mechanical energy is converted into electric energy for the electrical motor, the overall mechanical energy of your pedalling received by the rear wheel is roughly 20% less.

Poor performance when climbing

250 Wh electric motors alone barely deliver the extra energy required by uphill riding, even on not so steep climbs. On a standard ebike, leg power plays a decisive role when climbing, supporting the electric motor.

The technology is ready for cargo ebikes, probably not quite for other ebikes, notably for e-MTB

In 2013 Mando launched the Footloose, its digital drive ebike, so far the only such ebike for sale (chainless cargo ebikes are already on the market). Nine years later, I can find only one ebike online reseller offering the Footloose, based in London. If you look at the video below, the riding test shows the bike incapable of climbing on a slightly steep city road, although a similar test states slightly improved climbing performance for the new 2015 model.

Nevertheless, urban riding offers the possibility of frequently recharging the ebike battery through regenerative braking, rendering digital drive ebikes and e-cargo bikes much more efficient.

To say nothing about Mocci, a very promising digital drive ebike employing Schaeffler’s digital drives, which seems very advanced, having already started mass production for several cargo ebikes manufacturers.

Lack of natural biking feeling

Many ebike riders could probably complain about the different sensations experienced with a digital drive ebike. That happens anytime a new technology changes our sensations. There are people who dislike electric cars because they miss the motor noise of internal combustion engines. As if hearing noises when driving were more natural than enjoying a relaxing silence (!). That’s why we expect the same objections to adoption of digital drive ebikes, but there are going to fade away with time.

Why digital drives are being adopted first and mostly by cargo ebikes

There are quite a handful of ebike cargo manufacturers that are going to launch digital drive e-cargo bikes on the market in 2023. Indeed, this technology is particularly performant when it comes to e-cargo bikes, because:

• e-cargo bikes are particularly efficient for last mile e-commerce deliveries, whereby frequent stops allow to maximize the advantages of regenerative braking. The heavier the load, the more advantageous the regenerative braking.
• e-cargo bikes have often three or four wheels, which allows pedalling to generate electricity even when stopping at traffic lights.
• cities are normally flat.
• e-cargo bikes are expensive to maintain, especially because chains, cassettes ans sprocket suffer from heavy loads. Chainless drives require far less maintenance.

So, what’s your take regarding this innovative ebike drive?

Top image courtesy of Mocci