Chainless 4-Wheeled Hybrid Electric Bike Concept Is "Self-Charging"

The Hybrid Module Mobility concept isn't pedaled directly, but instead employs a pedal-powered alternator for riders to partially recharge its batteries.

There have been a number of different approaches to building chainless bicycles over the years, of which only belt drive systems seem to have gained any real traction with builders and riders, but that hasn't stopped people from trying. When it comes to a conventional bicycle, which has to transfer the rider's pedaling motion to the wheel, some form of a physical connection is required between the two, but for electric bikes which have a motor in the wheel, there's no actual need for a mechanical drivetrain between the pedals and the wheel, other than to qualify with certain e-bike regulations. Although with most electric bikes, the electric motor is used to boost to the rider's pedaling efforts, and not to completely replace them, there are plenty of throttle-controlled e-bikes that don't need to be pedaled to be ridden.

However, to completely separate the movement of the pedals of the bike from the movement of the wheel, mechanically speaking, is a bit different of an approach, and one that wasn't very well received when we covered it about 5 years ago. The Footloose electric bike, from South Korea's Mando Corporation, was dubbed a 'hybrid' electric bike, as it used a battery and electric motor system to move the bike, but it also integrated an alternator into the bottom bracket to convert the rider's pedaling motions into electricity to recharge the battery. Based on the battery and motor size, even the most ambitious cyclist would probably be hard-pressed to fully recharge the Footloose by pedaling, but it's clearly meant as a range extender, hence the hybrid designation.

The company, in collaboration with a team from the Graduate School of Creative Design Engineering at UNIST, is now said to be developing a different type of electric bike, this time with four wheels instead of two, and with the ability to be configured for six different purposes, but with the same 'chainless' drive system as the Footloose. According to UNIST, the Hybrid Module Mobility concept, which was revealed at the IAA Frankfurt Motor Show 2017, "is a new form of transport, aimed at European market," and can be set up as a front cargo carrier, a rear cargo carrier, or as several different variations of a passenger vehicle.

© Mando Corporation

According to UNIST, the resulting Mando Footloose Urban Modular E-bike "is not only capable of generating electricity through human pedaling, but also capable of storing that energy for later use," although there's no indication of the rate of charging by the alternator. The vehicle is said to have "eight large-capacity, multiple-connected, battery systems" that deliver electricity to the four in-wheel electric motors, but no details as to the estimated range, the battery capacity, or the size of the alternator have been revealed.

“This new hybrid system eliminates the need for having complex bicycle chains or mechanical driving mechanism, making it suitable for being applied to various platforms, including four-wheeled vehicles." - Professor Yunwoo Jeong of UNIST

Without knowing more about how much the range could be extended by pedaling the alternator, it's hard to say whether or not this aspect of the concept vehicle is actually useful, as opposed to just being a way to avoid being stranded with a dead battery.

According to a 2011 article from Low-Tech Magazine, "You have to pedal 2 to 3 times as hard or as long if you choose to power a device via electricity compared to powering the same device mechanically," which means that unless some radical efficiency improvements have been made on the UNIST-Mando concept vehicle, it might actually make more sense to drop the pedal/alternator part of the design altogether. After all, with a de-coupled drivetrain like this one, you can't manually pedal it home in the event of a dead battery, as you can with a conventional electric bike, and it may take quite a bit of time to generate enough of a charge with the pedals alone to continue onward.

That said, I like the idea of small modular electric vehicles that could transport people and cargo with a much smaller physical footprint, for both personal and commercial use, as long as the infrastructure is there to support it. If these are small and light enough to qualify as a bicycle, not a motor vehicle, then they will require plenty of riding lanes and paths, as well as charging stations in and around cities, to be both street-legal and useful enough to gain traction. Commercial applications, such as for deliveries and service calls, seem like a good fit for this type of vehicle, and due to their smaller size (compared with a traditional vehicle), they could be able to both help decrease congestion and local air pollution, but it does appear that diverging from the direct-pedal electric bike configuration may actually be less efficient than those being trialed by UPS and other delivery companies.