Spinning resistance of the Magic Pie

[reicher_89]

Hi there,

Before I purchase an internal Magic Pie, I was wondering if anyone could give me some specifications and insight on the "feel" of the Magic Pie...

- how hard/easy is it to spin manually when it is unpowered? (say riding a bike manually with no power to the Magic Pie, while the Magic Pie is just sitting, unpowered, on one of the tires)
-  what is the actual electrical (blackbox) resistance of the Magic Pie (36V interal controller) when testing the resistance from the positive power lead to the negative power lead?

Thank you so much for the help.

-Jared

[e-lmer]

I would not choose to ride the bike without power unless absolutely
necessary.  It is not that it is difficult to turn the wheel.

The problem comes from the fact that the wheel is over 12 pounds
and the battery at best is another 12 pounds, but probably more
along the lines of 15 or more if you go lead acid.
Add that to a 25 pound bike and you are hauling around more than
50 pounds of hardware.
(Do NOT try to minimize the weight of the bike, lightweight means
weaker, and you DO NOT want a broken fork or frame at 20MPH! )

The electrical characteristics of the controller are not very helpful in
most cases.  My guess is you are trying to determine the maximum
idle run time (under power but not in use). 

Trust me, this is a calculation for disaster.   
Batteries do not like to be run dead.  Even with a low voltage
cutoff, the cutoff circuitry takes power and drains the battery.
(My company has found this out with cell phones, don't leave batteries
in your cell phones and trust electronic cut-off.  It destroys the battery.)
Since a good battery pack is nearly $500 it is just not worth destroying.

[Webby]

From a practical standpoint it feels like this ..

In the event of a failure i.e. no power you would be forced to seek a low gear and on the flat you would be travelling at 8-10 m.p.h and the resistance on your thighs would feel like a very slight uphill pedal.

Ginge, Bikemad, Andrew, GM Canada - agree?

I've covered a lot of miles like others in this forum and fortunately I've never had to go into this  'limp home' mode once

[DirtyGinge]

Hi webbs :0 ...

Personally, I think if you can cycle on average 16mph, with a pie its 10-12, and always feels like a very slight uphill gradient..

8-12, not to bad

12 and more....quite hard

16+.....just no

[o00scorpion00o]

I can pedal the pie on flat ground @17 mph in high gear, up any kind of an incline is very tough there is a lot of drag with this motor!

When I first got the pie I was not as fit as I am now and lost 20 kgs since April which has probably helped a lot.

But if your intention is to pedal then get one of the Geared motors they have fantastic free wheeling ability, but afaik they are rated 350 watts max!

Check out GM's smaller geared motors, they pack a good punch if it's assistance you want and if you want to get fit there is NO better way to go.

The mini motor should be good for 350 watts max and should give decent up hill assistance. If it gets too hot to touch, then you know it's time to stop!

There are higher powered geared hubs out there!

But a bicycle with a pie and a battery no longer feels like a bicycle, it's very heavy.

It all boils down to this question

Do you enjoy cycling and cycle to keep fit?

If the answer is yes then the mini motor is the way to go!

Mark