Electric Bikes - Will this drive train work?

I am converting a beach bike to an ebike. I hope the attached paint pic will explain what I want to do. I want to get advice before I plunge into it in order to save money$$$ and avoid frustration.

The motor, on the left, is connected by chain or belt to the freewheel side of a gear hub. The speed will be reduced to about 1/3 of the motor speed with the sizing of the cogs on the motor and on the hub gear. The fixed side of the hub gear will be connected to the rear wheel by chain. Any additional reduction in speed will be done here. The hub gear will be a 3 speed. The crank is connected to the rear gear hub. All of the power transfers points for the motor are shown in red.

Will this:

1. Transmit the power from the motor to the rear wheel?
2. Will the rear wheel be going in the right direction?
3. Will the pedals automatically spin when the motor is being used, even if the rider is not pedaling?

it looks like it is complicated and would require a significant number of custom made parts.

The concept of how it works is basically sound though.

Pengyou, what exactly do you wish to accomplish that you feel cannot be done with a more 'conventional' layout/use of components? As mentioned your setup is complicated, perhaps overly so. Do you plan to use any of the gear changing capability of either hub? If you simply want a fixed 1/3 reduction there are more efficient ways than an internal gear hub in the low gear position. Do you want the pedals to spin when the motor is running? If so that is easily done. Have the motor connect to the crank either via a left side chainring or a second chainring on the right side. Now the motor/pedal system can go to a single 3sp (or more) rear hub. Simple and efficient. Just illustrate what your needs are and I am sure someone here can figure out how to get it done in a practical fashion.

H

Thanks! I do not want the pedals to spin - that would be easy to do. The front hub gear (3 sp) is not for speed reduction - that will be done via the chain/cog combo between the motor and the front hub on the right hand side. The front hub gear is to allow the motor to change speeds to suit the needs of the rider. The rear hub gear (5sp) is to allow me to pedal the bike efficiently at various speeds.

As far as making lots of custom parts is concerned, there are a few necessary but because of the layout of my bike and arrangement of the frame they will not be as complicated as it seems. I had to simplify the drawing because of my limited abilities so could not show you what it will look like.

I choose to split the drive train so that I would be able to add power. My gear needs and the motor's gearing needs are different. For example, if the motor is capable of generating a certain amount of force in first gear I might not be comfortable pedaling faster than that speed so that I could either add speed or save battery.

It would work, but in reality I can see no benefits over a BB drive, if the motor is geared to spin at the right cadence for your pedalling style yours and the motors gearing requirements will be very similar plus you will only have to shift with a single gear train instead of 2 seperate ones, which also means you can fit and have enough hands to operate a 27 speed derailleur system if desired.
Motor wise a low rpm hub motor can make for a nice silent BB drive.
I basically run the above system on my trike and it is very easy to use with a massive speed range on a very low powered hub motor (160w rating).

The front hub gear is to allow the motor to change speeds to suit the needs of the rider.

That isn't how it works. Since in your design the motor drives the hub and not the BB you don't have to gear it to your pedal cadence. In any case your range of cadence isn't wide enough to require an internal geared hub to match the motor rpm. Once you have the amount of reduction neccessary to put the motor rpm in the range of pedal cadence you are done with further gearing changes as far as cadence is concerned. Thing is, you might want a wider range of road speed than you can get from a fixed final drive ratio. That is what you want for yourself and your motor wouldn't mind getting in on some of that action as well. Or not, your choice. You are a good candidate for a 'Pedelec' controller which monitors your pedal cadence and adds a controllable ratio of motor power to your pedal power. GeeBee is very correct, you cannot hope to monitor two separate systems of motive power and gear them separately. Either do what he says and use a hub motor that already spins at wheel cadence, or gear your motor directly to the left side of a 5sp geared hub and your front chainrings to the right side of the same hub OR gear your motor to your chainrings and connect both to the right side of the 5sp rear hub. Most non-hub motors spin in the 3,000rpm range. Most rear wheels spin in the 300rpm? range. Pedal cadence as you know could be 50, 60, - 100+ rpm. You will have to figure the appropriate reductions depending on what you decide, it still is easier than using two separate gearsets.

H