The Electrom is a new type of vehicle carving out a place in the modern transportation network. With any new type of vehicle there come new design challenges that require fresh solutions.
A simple question like, “how do you keep it upright while you’re getting on and off?”, required some careful design work that resulted in our Forward Mounted Centre Stand.
Different questions led to other innovations for other problems such as the steering system and the Generator Chain Drive, learn more about them below.
Generator & Chain Drive System (GCD)
Many electric bikes are really just electric scooters with pedals attached to exploit ebike standards as a loophole. Not the Electrom, it is designed to be pedalled. The Electrom uses a unique Generator & Chain Drive System (GCD). The GCD acts like an automatic transmission for a bike.
How it works:
The rider’s energy is split and goes via two separate drive chains to both an on-board generator as well as to the back hub motor with one very low gear. The rider can help the motor get the vehicle up to speed and to climb steep hills with direct pedal energy, but at speeds over 15 kilometers per hour, the chain drive is freewheeling and the rider’s energy is going solely into the generator.
Benefits of the GCD system:
No Gears – It allows the rider to pedal all the time at a constant effort without the need to shift gears to match the human energy to the speed the vehicle is traveling. This is especially advantageous in stop-and-go city situations.
High quality exercise – Because the rider’s efforts are independent from the speed of the vehicle, they can pedal all the time against a constant resistance, even when going down steep hills or slowing down. This makes for a superior quality of exercise. The Electrom pedalling station is mounted high enough off the ground that there is no possibility of pedal-strike on tight corners which adds to the time one can spend pedalling.
Choose your effort – Because the rider can pedal as little or as much as they want, they have the choice of working hard and sweating, or pedalling at a gentle pace with efforts similar to walking. This is a nice feature if one is on their way to work in an office situation.
Track power output – The human power generated by the GCD system is routed through a shunt and displayed in watts on the Grin Cycle Analyst V3 display.
Low maintenance – While the GCD may sound complex, the mechanisms that make it work are quite simple and time-tested. Because the drivetrain is under very little strain it does not stretch or wear out like a conventional bicycle drive-train and requires very little maintenance.
Dual motors for power & efficiency
The beauty of hub motors is that they allow for a straightforward way to add a driven front wheel to a bicycle. The Electrom takes full advantage of this by using two different types of hub motors with different characteristics.
Back Wheel – For the back wheel we are using a direct-drive hub motor that is mechanically very simple, supports regenerative braking and is very efficient once it is at cruising speed. The downside of direct-drive hub motors is that they are heavy and inefficient at low speeds. Because there is no gear reduction between the motor and the hub they require a huge amount of power to start up and to climb hills.
Front Wheel – On the front fork we have a much lighter geared hub motor that uses a smaller motor and gear reduction to produce more thrust-per-watt than the direct drive motor. This front motor helps get the bike up to speed and to climb steep hills, but once the Electrom is at cruising speed, the front motor shuts down to save power. Because there is also a freewheel between the motor and the hub, there is no drag from the motor when it is not running.
The combination of these two motor types on the Electrom provides far more power and traction than a single motor and aids efficiency because the Front Hub Motor helps get the bike up to speed quickly but then shuts down at speeds over 28 km/h to save energy. The rear Direct Drive motor is more efficient at higher speeds and is able to employ regenerative braking to help slow the Electrom down while returning power to the battery. Regenerative Braking also helps save wear on brake pads.
When we implemented this system we immediately saw an increase in range and efficiency because the bike could climbs hills and gets up to speed while consuming far less power. The all-wheel-drive traction was pretty awesome as well.
Aircraft Cable Remote Steering system
One of the hardest problems to solve with long wheelbase bikes such as the Electrom is how to make a dependable and precise Remote-Steering system. A Remote-Steer describes a situation where the handlebars are not directly connected to the front wheel.
Bicycle remote steer systems are often imprecise due to flex in the components. To solve this problem the Electrom uses a patent-pending remote steering system that utilizes time tested principals of aircraft control systems.
The Electrom steering system employs a tensioned loop of cable and two pulleys; one mounted to the handlebars, and one to the underside of the fork crown. The system is very smooth and natural feeling, which is a must on a two-wheel vehicle. Because the Electrom has a powered front wheel, the steering system must also be very strong and precise with no flex or slop.
The Electrom steering system has also been designed for longevity and safety. The cable uses is aircraft grade 27 strand 3/16ths stainless steel and the pulley’s used are properly sized for the situation. Similar to an aircraft, the system is inspectable and–should it ever be required–the cable is replaceable.
The prototype system is still in use on our test bike, with over 10,000km of use and no sign of wear.
Forward Mounted Centre Stand
When an e-bike crosses over the weight and size threshold from bicycle to vehicle, one needs to consider issues that may have been an afterthought on a bicycle but are now critical to the new vehicle. The Electrom required a dependable kickstand that was easy to deploy before getting out of the seat.
As necessity is the mother of invention, we came up with our unique Forward Mounted Centre Stand. This is a simple device that allows the rider to put the Electrom into a stable parked position before getting off the bike. The stand is easily deployed with the rider’s foot, spring loaded for a quick return, and held out of the way by a magnetic catch while traveling. The rider can also roll off of the stand from a stop.
One of the unexpected benefits of the system is that it is so easy to use that it can also be deployed while at short stops at traffic lights and the rider can simply start up to come off of the stand and ride away. The Forward Mounted Centre Stand is one of those useful and simple things that, upon reflection, you wonder why it hasn’t been around for decades.
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