Smart Pie or MP4 Vector together with CA V3

[Hastings]

Hi
I need your help to decide- it is time to choose the rear wheel for my new build. I have today a MPIII with a 48v 15ah PING battery(giving me 40-45 km on a charge if I peddle, I have 30 km back and forth to work. ) with a twist throttle. It is definitely strong enough  but the temptation to always go flat out which gives too little training. Also the weight is too high and  too rear centered .
First what I want to accomplish:  I have an undiagnosed lung condition possibly an early fibrosis with a loss of 30-40% of my lung function, but has been stable for the last years. If I exert myself too much I get a persistent cough and lower oxygen saturation for days. I can exercise and get in much better shape if I do-as long as it is steady low impact= Skiing and skating in winter and Electric bike in the summer.. I should be able to pedal up 70 % of power required on the flats -if I exceed a low set cruise it is hard to keep speed as there is an immediate cutoff of power .

So my new build is a lighter 29er hardtail mountainbike on city tires I will try to fit a 10ah 48vPing battery into the frame. I will use a Thun torque BB and a V3 Cycle analyst with a potentiometer and external shunt. I have managed to fit external hall sensors to the hydraulic brakes using a milled Lexan plate and a thermoformed PE to hold the magnets

I was hoping that I could control trust and total torque  and had decided to go with a Smart pie or a freewheeling motor to have lower roll resistance- It is a pitty that there is no function in the controller to null roll resistance  once cruise speed is exceeded! I hope to be able to use more motor power in the hilly sections by twisting the potentiometer.

Lately I have been thinking that the Smart pie is to weak for hills- and that I can "dial down" the power of a MP4 vector enough to achieve some training. What is your take on this?

Will it use to much power ?I want  at least 30 km of range. I can charge booth at work and at home

[Bikemad]

If you need the assistance on steep hills then the Smart Pie is definitely going to struggle with a 29" wheel unless you are unable to provide a fair amount of pedal power yourself.

Why don't you try lowering the current settings on your existing MPIII to see if it will provide the additional exercise that you are aiming for? If this is successful, you can go with the MP4 knowing that the power will be more than adequate, but can be adjusted using the Cycle Analyst to provide the required assistance at all speeds.

Another alternative would be to use a pair of Smart Pies for better weight distribution and double the power for hill climbing. If you fitted a DPDT ON-ON-ON switch to the throttle signal wires you could easily select front, rear or both wheel drive:



Alan
 

[Hastings]

Thanks Alan -as usual why didn't I think of applying the cycle analyst to my present bike?
Will do that. Too bad I don't know anyone with a Smart Pie here in Stockholm.
This is my new build: