cute hub motor mid mounted..

[Haste]

still pondering this idea...

fast wind 24v motor overvolted to 48v....running maybe 20amps...will it hold up however?

It freewheels...great for a mid mounted build. I just want something to tear up the trails with..and have good topend as well. The bicycle rear cassette(32-11t) I believe should net me both of each world.

48 x 20= 960watts....for a 500w rated motor. I mean I see no reason why it would not hold up...25 amps would be ideal however.

I could even go with the smaller width front hub, and mount my freewheel to the disc mount area...but that would rid me of freewheeling ability. I just have no idea how to secure a sprocket to aluminum freewheel side. Cut the axle length down, and remove the flanges=cheap and easy cheap "RC" motor.

Running lower amps would also make me purchase a cheaper 10ah battery aswell...since im sure the effiency is even greater going 30mph in 11t gear..


sorry for meh bad english...

 

[Haste]

[youtube]http://www.youtube.com/watch?v=rXnssYyYUlY&feature=channel&list=UL[/youtube]

seems someone has done it...but Im sure he is running 36v..so bump it to 48 with more amps....should have power...

 

[etard]

The germans have done this for ultra efficiency, not sure where the thread is, probably posted 2 years ago. Keep the flanges for heat dispersion. I would use a bigger motor personally. Have you seen Whiplash's mid drive?

 

[Thud]

hehe, i was just at the BMs site looking at these with this in mind

to make the youtbe work just put this part between the bracketed stuff
rXnssYyYUlY
[youtube]rXnssYyYUlY[/youtube]

this guy has it teribly overgeared but it should be a doable & cool project.

 

[whereswally606]

what about welding a flange to a old steel bottom bracket cup drill six holes in the flange to mount to the disc holes on the motor and use a 16tooth bmx ACS freewheel to fit onto the thread of the bottom bracket cup. its what i intend to do to my 80100 motor eventually but i see no reason that it wouldnt work for you here. its about the cheapest way i could think of. Ive got the materials at home but alas im 200 miles west at uni.

 

[bzhwindtalker]

Does those motors accept to run in reverse? Because if they do, the front hub and disc mounted sproket thing would be ideal.

 

[Lebowski]

I've been thinking in the same direction. Swap out the left side crank for a right side one with
big chain wheel. Mount a Qute100 or Bafang front wheel motor to the seatpost. Run a chain of a
small sprocket (attached using the front disc mounting threads) to the left crank. A hub with an
internal freewheel would be the best.

 

[amberwolf]

what about welding a flange to a old steel bottom bracket cup drill six holes in the flange to mount to the disc holes on the motor and use a 16tooth bmx ACS freewheel to fit onto the thread of the bottom bracket cup.

Even simpler, is to use the righthand side of a rear threaded wheel hub, like I did here:
http://www.endless-sphere.com/forums/viewtopic.php?p=551146#p551146

Except you would drill it out to the six-hole disc mount pattern instead (whcih I didn't have on my hub).


FWIW, I suspect that a tiny motor like the Cute may not take well to overvolting unless you severely limit the current. If you're using it as a middrive, you don't generally need it to spin really fast anyway, as you want likely 80-100RPM max into the bike's drivetrain. (assuming you're not running a separate chain to the wheel instead). My little 36V Fusin geared hub gets pretty hot at 48V even with only 20A or less max currrent, and not even drawing that much, if I run it at a lower speed (partial throttle). Might be mitigated if I ran it thru the gears, but haven't got around to the testbed for that yet.


To help with the heating problem, oil-cooling for keeping it sealed up should work, or at least help. Alternately, if you don't need it sealed, there's a lot of ventilation you can do on a geared hub that cant' be done on a DD: Slot the area between the spoke flanges, and add centrifugal fan vanes there, then add holes for air entry near the axle on both sides. I think John in CR first suggested this; at the least there is a discussion about it in a thread of his about Fusins and other geared hubs as middrives.

What I plan to try with a similar-to-the-Cute-sized TongXin "geared" hub is to leave the entire outer shell off, as it's design doesn't require that part for operation or to run the "gear" reduction. This should help immensely with cooling issues, since I will likely run it a lot harder than it was meant to be.
http://www.endless-sphere.com/forums/viewtopic.php?p=511519#p511519

 

[Phoebus]

I'm interested to see how these little motors hold up to real world mid drive use... suspect that for many applications, not many volts & amps would be needed... Could be interesting.

 

[Whiplash]

The only thing I can say is don't over gear it so much that it has to spin slower than it would in the wheel. With the bikes gears and a mid drive its very easy to force the little motor to lug around in the higher gears and this will lead to overheating and broken gear teeth. I recommend gearing it as close to 1:1 in high gear as you can, then eeduce from there for the lower gears.

Just my $.02 from experience.

 

[Lebowski]

From the gym I know I like to cycle around 80 feet-rpm... With a left side crank with a 44 tooth sprocket
a 15 tooth on the motor would give around 240 motor rpm (bit less than 20mph in a 26" rim).
Using a 48v battery with a 36V motor, I would imagine this would work ?

 

[Tench]

I tend to agree with Whip, gear it so the fastest gear gives a 1-1 ratio between motor and wheel, the individual chain wheel sizes can be selected to give the pedal cadence you prefere. The over volting will result in higher motor rpm's so it may even want gearing lower than 1-1?

Simon.

 

[Lebowski]

I overvolt as standard, I use a controller with sinewave out
(which by definition has a lower RMS output compared to squarewave out)

for my 2nd project I'm thinking about building a Dutch style (3 gear hub ?, like
http://www.gazelle.nl/Collectie/Stadsfietsen/Lifestyle/66-Degrees ) bicycle that will
climb 8 to 10 % hills with ease. Max speed should be 25 kmh, 500W max (to stay legal).

First I'll look whether I can find a frame to build from scratch, I still got a good 28" wheel
with a Nuvinci N360 in the garage....

 

[deVries]

I overvolt as standard, I use a controller with sinewave out
(which by definition has a lower RMS output compared to squarewave out)

for my 2nd project I'm thinking about building a Dutch style (3 gear hub ?, like
http://www.gazelle.nl/Collectie/Stadsfietsen/Lifestyle/66-Degrees ) bicycle that will
climb 8 to 10 % hills with ease. Max speed should be 25 kmh, 500W max (to stay legal).

First I'll look whether I can find a frame to build from scratch, I still got a good 28" wheel
with a Nuvinci N360 in the garage....

This will likely be a mid-BB-drive on the left side then?

I'll look forward to the build thread, as that is exactly what I've considered doing for over a year now!

 

[d8veh]

I had a go at it with a Bafang 250w front motor. I made up various brackets and fixings with simple tools. With a 14T sprocket on the motor and 42 (or 44T can't remember) on the crank, the gearing was perfect, giving max power at a cadence of about 70rpm - my natural pedalling speed. It could pull up very steep hills without pedalling and would go quite fast on the flat with 15amps. However, my mounting brackets weren't rigid enough so the chain jumped the sprockets in the highest gears, where the torque demand was highest. My freewheel was on the motor.

I'm going to have another go soon with rigid carbon fibre brackets. I want to use the BB to hold two plates, which extend forward to hold the motor so that the distance between centres is fixed. I already have a free-wheel crankset from Cyclone, which I'll lighten a bit for this project.

Here's some photos and a video of my first attempt:
http://s451.photobucket.com/albums/qq236/d8veh/Crank%20drive/
http://www.youtube.com/watch?v=qfWSQh8cAzI

 

[stoney]

Anything new to update?