I build motorized bicycles for a living and most are gas, but I saved the last of my rare Kent built Cadillac Fleetwood bicycles with the NuVinci CVP infinitely variable internal rear hub for an electric shifting conversion and this is it.
About the Bicycle:
The Caddy is rare bicycle, it was an attempt to introduce NuVinci's gearless shifting hub to pedal pushers and because of the weight it failed miserably and were only made for about a year.
Caddies failed with pedal pushers despite the looks but pretty great with motor power assist that take advantage of that transmission.
This particular bike is not stock, I put a dual spring front fork with V-brakes and different handlebars on it.
About the Drive Train:
The Bottom Bracket is the 'magic' part.
At the top is the 36V LiFePo battery attached to seat post with the Cyclone CY960W controller mounted in front of it cooling fins facing the wind.
In the middle is the 24-48V Cyclone CY-650~1200W BLDC Motor with a freewheel sprocket secured with muffler clamp brackets.
At the bottom the entire 1-piece crank arm assembly was removed and via adapters a new sealed bearing cartridge shaft with a slightly longer left side reach so the left crank arm would clear the motor was installed.
The 'magic' part is the specialty parts that lets 2 sprockets (chain to wheel and chain to motor)to be tied together but let the pedals freewheel, or ratchet, when no pedal power is applied.
On a bicycle the front chain rings are directly attached together and to the right crank arm, which via the shaft attached to the left crank arm and pedal.
I have pictures of this somewhere and will post them when I find them but in short it consists of a freewheel bearing with threads on the inside that the special right crank arm screws into, and a round 5 hole flange of the outside for the pair of sprockets to bolt to.
The result is the pedals are no longer connected to the bicycles drive train sprockets unless you pedal thus leaving the motor to spin the pedal sprockets together and your pedals don't move.
That bike will do 35MPH without breaking a sweat, just not for long. I love it though ;-}