The Problem
We believe that one of the most significant impediments to making bicycle transportation ubiquitous in our society can be easily overcome and is often overlooked. It is the design of the conventional bicycle itself. Unlike most modern products, bicycles require the user to adapt her body to fit the machine’s requirements, instead of the other way around. This machine-centric design causes many people to experience significant discomfort when riding (e.g., pelvic pain and numbness, lower back pain, shoulder and neck pain). We believe that this discomfort presents a tremendous barrier to achieving mass adoption of the conventional bicycle in our society. Three years ago, we began an effort to fix that.
Our Proposed Solution
Our proposed solution was a user-centric bicycle design that accommodated the natural human mechanism for propulsion: walking.
Design challenges
The fundamental design challenge we faced was creating a device that successfully emulated the kinematics of walking/running and was light, ergonomic, structurally sound, and fun to ride. To mimic the running/walking motion without the impact we used an offset slider crank mechanism acting on an inclined plane as the rider interface to the drive-train. This linkage was then coupled to an 8-speed internally geared hub via a chain drive to enable the rider to adjust his level of exertion over varied terrain.
We designed the tubular steel frame in a sweeping truss to create a high stiffness-to-weight ratio. This approach enabled sufficient stiffness across a 27-inch stride length without the need to place frame structures between the rider's legs.
The Result
The result of our efforts is the “elliptiGO”. The elliptiGO rider stands on two pedaling platforms and powers the bike via a walking or running motion. The rider uses standard bike controls to steer, brake, and shift gears.
To control costs, the elliptiGO uses standard bicycle components throughout and standard bicycle frame-building techniques. Although we are still in the test-and-learn phase of development, we have noted a number of advantages over conventional bicycles:
Comfort: The riding position and pedaling motion eliminate the pelvic, back, shoulder, and neck pain associated with conventional cycling.
Safety: The upright riding position improves sight lines and visibility.
Performance: The elliptiGO averaged 15 mph during a 50-mile test ride that included 2800 feet of climbing. The bike’s steering, braking, and stability at all speeds (even below 3 mph) are similar to a conventional bicycle’s.