Am I crazy

[Dasmailca]

I would like to add an electric motor ( front wheel ) to my gas powered motorized bike to make it a hybrid. Is this feasible ? I am confused as to which motor to use and which battery to match with motor.

[Bikemad]

Hi andto the forum.

Fitting an electric front hub-motor should certainly be feasible, but the choice of motor and battery will depend on many factors including the following:

• What size front wheel do you have at the moment?
• What is the current maximum speed of the bike on the gas motor?
• What is the current all up weight of bike including the motor, fuel, luggage and rider?
• Will it be run on just electric power at times?
• What range are you hoping for?
• Do you have many steep hills on your typical journeys
• What size budget do you have set aside for this project?

If you can provide the answers to the above questions it will be easier to come up with some useful and relevant suggestions regarding the choice of motor and battery.

Alan
 

[Dasmailca]

Thank you for your response.
•Current wheel size is 700c
•Maximum speed is 30 mph,however I would say that I ride in the 20-25 mph range when conditions permit. The maximum for power assisted bikes in my comunity is 32 kilometres per hour(approx. 20 mph)
•I can lift the bike onto the car bike carrier, so I think it is less than 50 lbs. rider is 170. I can get a little more precise on this later.
•I would like to have the option to run on electric only. I would like to start from a dead stop with electric.
• Range      30 miles ?
•There are steep hills most of which can be avoided. All that I have tried have been handled ok but some help would be nice. (I peddle too)
•From the little bit of research that I have done it looks like $800 ?
 In this case less is better. Lol. But 1000. Is not out of the question.

[Bikemad]

I think for your particular use, the Magic Pie III might be the best motor to use, as the larger diameter motor produces a considerable amount of torque (and strong regenerative braking force) which should come in very handy with a large 700c wheel.
The built in controller combined with simple "plug and play" wiring makes the installation a lot easier too.

Another option would be the Smart Pie, which is a lot smaller, lighter and also slightly cheaper than the MPIII, but produces a lot less torque (and has much lower regenerative braking force) because its physically smaller size.
The biggest advantage I find with the Smart Pie (apart from its cost, size and weight) is the almost undetectable amount of drag that it produces when not being powered, in comparison to the MPIII, which might be a big advantage when you're running the gas motor without the assistance of the electric motor.
The Smart Pie also has a built in controller and comes with the same simple to install wiring and controls as the MPIII.

The Pro 901 motor would be your cheapest option, but it produces less torque than the MPIII and is not disc brake compatible. It would also require additional space to house the separate controller and all the associated wiring.

To achieve 25mph on electric power you will require a 48V battery, but the 48V 10Ah pack is not going to manage a range of 30 miles without a lot of pedalling or gas motor assistance, especially when there are hills involved.
I suspect the 48V 15Ah pack would even require assistance to achieve a 30 mile trip involving hills.

If you currently have aluminium forks, you will need to replace them with steel forks that are able to withstand the torque being transmitted through the axle, and I strongly recommend using torque arms for additional safety.

The MPIII and the Smart Pie are both compatible with conventional "V" brakes or disc brakes, so either should work fine with your existing brake set-up.

If you currently use a twist throttle for your gas motor you will need to fit a thumb throttle control for the electric motor so that both motors can be controlled with one hand. 

Alan
 

[Dasmailca]

This is my fork, do I need to change it ?
http://www.srsuntour-cycling.com/dstore/products/Forks/2640/M/SF10-M3000-AL+26'.html?sid=1

I live in Canada and we are on metric but I try to convert for my American friends. I said 30 mile range but would be happy with 35 Kms.
Torque arms sounds good.
I am leaning to MP III But do like lightness of Magic Pie. Would it start bike from standing start ?
Thanks for your interest and reply.

[Dasmailca]

Also I have a late sixties or early seventies CCM tandem hanging in my garage that I would like to electrify. Any suggestions ?

[Bikemad]

This is my fork, do I need to change it ?
http://www.srsuntour-cycling.com/dstore/products/Forks/2640/M/SF10-M3000-AL+26'.html?sid=1

I would think those suspension forks should be OK to use provided a pair of suitable torque arms are fitted, but you might need to modify two of the supplied axle washers to fit properly inside the "C" shaped recesses on the outside of the fork dropouts to provide a nice flat surface for the torque arms to press against when the axle nut is tightened:



The outside diameter of the washers should be small enough to just fit inside the recess and should ideally be chamfered/radiused on the outer edge of the inner surface so that it does not apply any outward force at the outer edge of the washer.
If the washer is too large (or not chamfered or radiused to allow clearance for the fillet inside the recess) just tightening the axle nuts could exert enough pressure to force the dropouts apart causing the casting to crack:

I am leaning to MP III But do like lightness of Magic Smart Pie. Would it start bike from standing start ?

Both motors would pull away from stationary on the level and on slight inclines, but the MPIII would pull away quicker and would also tackle much steeper inclines on its own, whereas the Smart Pie would definitely need some pedal assistance on steeper slopes.

Also I have a late sixties or early seventies CCM tandem hanging in my garage that I would like to electrify. Any suggestions ?

This depends on the way you intend to ride it. If it will be ridden mainly with power assistance and on steeper hills, I would use a front mounted Magic Pie.

If it is going to be mainly pedal power, but using the motor assistance just on hills and in strong headwinds, then I would probably use a front mounted Smart Pie instead.

I would also recommend fitting a brake on the rear for additional safety. Relying solely on a single front brake to stop the total weight of the bike, two riders, motor, battery and luggage etc. on any incline is asking for trouble.
Imagine what could happen if the brake cable snapped (or pulled through the clamping bolt) under hard braking on a steep hill!

Alan