ken via EV<[email protected]> wrote:
>> I have a Bike E with 20" back wheel. Where can I find a reasonably
>> priced wheel that's designed to be efficent for that RPM / 20- 25 mph
>> and 36 volts.
Michael Ross via EV wrote:
Better check me, I get 335 RPM at 20mph and 419 RPM at 25 mph
36 volts will get you less torque than 48 volts. Probably not a problem
with a light bike like a Bike E.
It will be quite tricky to lace such a wheel up as the spokes will have to
be very short. Consider radial lacing (no crossing spokes).
I didn't think you could use radial spokes with a powered wheel (can't
handle the torque).
Honestly, I think you would be better off rigging up a mid drive.
I agree. I also have a Bike-E, and have been thinking of ways to E-bike
it. But it has a 7-speed rear hub. You'd lose that if you go to a
powered wheel, which could make it pretty hard to ride under pedal power.
I have a Giant LaFree E-bike. Its motor has a small sprocket with a
freewheel on it, which drives the chain. The rear wheel does not have to
be modified at all, and the motor benefits from whatever gearing you
have on the back wheel. This setup has worked very well. The only
challenge would be to find an appropriately sized freewheel sprocket for
the motor.
I also have a couple of "Warrior" E-bike friction-drive motor setups.
They aren't as efficient, but you can lift them off the tire when not
needed to have zero effect on efficiency. Yes, they slip when wet and
can cause faster tire wear; but it's a mighty easy system to put
together in a hurry for testing/evaluation.
I have a conventional 26" bike with a front hub motor. It works, but I
really don't like it. It degrades handling, and the front wheel is
inclined to slip if you apply enough torque to be more than a gentle
thrust. I think a front-drive setup would be even worse on a Bike-E.
--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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