Alan Cross is a veterinary orthopedic surgeon in Atlanta, Georgia, who also has a degree in engineering. In his spare time he designs and builds neat stuff, like electric drift bikes and steampunk floor lamps. And the ExoDyne electric motorcycle.
Revealed on Silodrome.com, the skeletal machine is the result of just nine months of design and fabrication, all realized by Cross himself working in his garage. The only items outsourced were the powdercoating and seat upholstery. Cross grafted the inverted fork from a 2005 Suzuki RMZ 250, while the steering head and swingarm came from a 1995 RM 125. The Ohlins shock bolts to a triangulated mount at the middle of the frame box. Tidy.
The frame doubles as the battery box, set in a straight line between the steering head and swingarm pivot. The frame member encloses 48 lithium-ion polymer batteries configured in a 110V/32Ah system, providing a potential 600 A output but limited to 200 Ah. The integrated frame/battery assembly weighs 48 pounds.
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Rather than a liquid electrolyte, the batteries employ a polymer electrolyte that produces a higher specific energy rating than standard lithium batteries. The result is more power from less weight. A CycleAnalyst instrument panel displays speed, amperage, and remaining charge.
The 11 Kw EnerTrac motor in the rear hub produces peak power of 30 Kw, modulated by a Sevcon Gen 4 controller. Rear hub motors have become the most popular choice for electric motorcycles, reducing both weight and power loss in the drivetrain. The Warp 9 wheels are fitted with a Brembo brake system in front and a Suzuki unit at the rear. ProBolt titanium and aluminum bolts were used throughout the chassis. Total weight is 248 pounds, top speed is about 60 miles-per-hour, and range is 20 miles.
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Cross has no production plans for the Exodyne, and intends to sell it to fund his next project. Garage-built specials of any type rarely display this level of craftsmanship, but Cross’s work is a good example of what a talented designer/engineer/builder with a concept can do in his spare time.