I've always wanted to write a Motor-Trend/ Car-and-Driver/ Road-and-Track headline. Now that I have, I must take a shower.
Marcus Hays, founder and CEO of Electrobike, kindly allowed me to test ride this prototype for a new Electrobike Pi. The bike is clearly still in the final developement stage: The monocoque spar frame is the only major component whose design is finalized. And even it wasn't yet painted. Some components on this prototype were machined, or adjustable for testing: the chain stay is a one-off piece of machined aluminium that carries the bottom bracket and electric motor. The riding position is being worked out with adjustable handlebars. The design of the chain stay, and deletion of the seat post is the biggest visual difference between this and earlier Pi models. This test mule had an internal geared 4-speed rear hub that will be replaced with a single gear when the new electric motor is installed.
The prototype is designed within the legal constraints of the DMV's definition of a bicyle: The engine is at most 1hp, and top speed limited to 20 mph. Anything more than that and it would have to be registered as a moped or motorcycle. That's not to say Hays hasn't built an "unlimited" Pi. The 30hp Pi X gas electric hybrid Bonneville Racer is awesome.
So, how does it ride?
First, Hays adjusted the seat to fit me. The seat "post" is a parallelogram design that moves the seat down and forward for smaller riders. Nice. There's a keyed "ignition" for security. Below the key is a 12 volt outlet for accessories. The riding position is similar to a cruiser bike. The "throttle" is a small lever on the left of the handlebars, and the brakes are hydraulic discs (the front brake was still being assembled, so I couldn't test the stopping power).
I stepped on the pedals in first gear and the Pi moved forward. I then engaged the electric motor with my left thumb. The bike accelerated firmly with the low speed torque typical of electric motors. The bike was very well balanced and easy to control in slow turns. I stopped. Clicked it into second gear and accelerated again. It felt a bit sluggish this time. But remember this is not the production motor and gearing combination the public will eventually get. And the geared hub was probably there just to test various gear ratios.
Conclusion: While the Pi is worthy of an industrial design award, it is also practical transportation that is legal to ride anywhere a bicycle is allowed. The visual strength of the spar frame is as impressive as the light balanced handling.
25+ mile range
36-volt nickel metal hydride batteries
Recharges in 2.5 hours from a household outlet
Today I was able to examine the prototype's final design. The final components were in place. The internal hub gears in the rear wheel is an automatically variable item. Marcus said the gear range is equivalent to 10-speed cassette.
The front fork now has trailing arm suspension (designed by Martin), with the springs/shock cleanly hidden on the inside surface of the fork.
The parallelogram seat 'post' has been refined to perfection. There is a fine adjustment for the tilt of the saddle, and a quick-release lever to lock everything in place. The throttle lever is on the right of the handlebar.
The final design is for sale on the PiCycle web site.
It differs from what I thought would be the final design in that the motor is in the front wheel. I guess that change had to be made once the decision was made to use an internal geared rear hub on the production bike.
Cool name and it looks good.
Categories:Cars Design Science