Hub Motor To Drive The Chain?
- Thread starter kitchenman
- Start date
Heh. Not so much doing as thinking. I still can't decide if this is a good idea or a silly one. And it's full of gotchas. I still think the kinds of motors we use would benefit from a 2 speed gearbox so you could get high torque-low speed for hill climbing and low torque-high speed for economy and outright speed. But actually achieving that is hard. If you have a long bike like a recumbent, trike or cargo bike with a long chain run then it's perhaps worth pursuing.
Can you not just buy chain drive kits though?
The only thing I can really see the benifit of doing this is if you had a spare motor doing nothing.
Else your using a motor not intended or build for that purpose.
Also it would work better with a Direct drive as they have beeter cooling.
The only thing I can really see the benifit of doing this is if you had a spare motor doing nothing.
Else your using a motor not intended or build for that purpose.
Also it would work better with a Direct drive as they have beeter cooling.
D
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I'm having a go at building one. I've got the motor and made the sprocket and fixings for it. I've stopped working on it while I build my trailer and trailer bike for Presteign, so I'll be continuing after that weekend. I can see how to work it with the throttle, but I'm still thinking about how to use a pedal sensor The problem is that my pedalling will turn the crank, which'll kick the motor into life, but the motor will also turn the crank, so there'll be no way of stopping it. Anybody got any ideas?
I don't like the idea of the motor driving the crank. Or of a freewheel in the crank sprocket. So my thinking was all around trying to arrange for two sprockets on the motor and two chains. Crank to freewheel on the motor, then motor fixed sprocket to conventional rear derailleur. Various problems present themselves such as the motor cover undoing itself, not enough spline on the motor for 2 sprockets, fixed sprocket trying to undo itself. And possibly internal motor freewheel working in the wrong direction. This is the Cyclone mid motor, twin sprocket arrangement but trying to use a better quality motor, controller and gearbox than the Cyclone.
If you do all that then the PAS become easy. You can run motor+pedals, motor and freewheeling pedals, or pedal and freewheeling motor just as with a normal hub motor.
If you do all that then the PAS become easy. You can run motor+pedals, motor and freewheeling pedals, or pedal and freewheeling motor just as with a normal hub motor.
Put a freewheel on the crank/chainrings, so the crank only turns when you pedal. The motor still drives the chainrings without the pedals/crank turning. That’s the way the Cyclone system works, I use PAS with my setup OK.
Chris
The Swizzbee used a Heinzmann motor mounted high in the rear frame triangle behind the seatpost, driving the left hand side of the unique drive-sharing transmission via a belt.
The Stokemonkey motor below that's used with the Xtracycle frame extension is rather like using a hub motor:
.
The Stokemonkey motor below that's used with the Xtracycle frame extension is rather like using a hub motor:
.
I'm thinking of stripping off the electrics on my CX700 and installing on my recumbent as a chain drive solution ....
I am in the process of creating a crank driven system.
I was looking to increase my cruising speed and make the motor more efficient at going up hills using my current limiter to keep overall power control.
I am using my first Tongxin motor in a broken casing. I turned off the spoke flanges to make it smooth and gain greater clearance to the frame.
It was going to be a 'stealth' system on my marin urban bike.
After machining off the inside threads I pressed a 12t fixed wheel sprocket onto the casing. Fits a treat.
I then made up a bracket to intially mount it on the drinks bottle holes temporarly to try it out.
Everything was fine until the bracket wobbled and threw the change which jammed up the crank making me resort to pushing it home...ah well it worked well up until that point.
Sorry don't have any photos of the motor in place (or the finished bracket)because of the slight breakdown.
Nevertheless, i am going to pursue it, but i now know, i need a steel framed bike to tig weld brackets in place. The motor and chain extert quite a strong force on everything.
When i find the right bike(ebay) i will post more pictures.
I was looking to increase my cruising speed and make the motor more efficient at going up hills using my current limiter to keep overall power control.
I am using my first Tongxin motor in a broken casing. I turned off the spoke flanges to make it smooth and gain greater clearance to the frame.
It was going to be a 'stealth' system on my marin urban bike.
After machining off the inside threads I pressed a 12t fixed wheel sprocket onto the casing. Fits a treat.
I then made up a bracket to intially mount it on the drinks bottle holes temporarly to try it out.
Everything was fine until the bracket wobbled and threw the change which jammed up the crank making me resort to pushing it home...ah well it worked well up until that point.
Sorry don't have any photos of the motor in place (or the finished bracket)because of the slight breakdown.
Nevertheless, i am going to pursue it, but i now know, i need a steel framed bike to tig weld brackets in place. The motor and chain extert quite a strong force on everything.
When i find the right bike(ebay) i will post more pictures.
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Hi Mel, Any progress? I'm thinking of doing something similar. Although I was thinking to fit another crank and copy the stokemonkey config.
Big Dummy with Stokemonkey electric assist - Go By Bike Episode 18 - YouTube
Big Dummy with Stokemonkey electric assist - Go By Bike Episode 18 - YouTube
Although .... if you can press one sprocket then I suppose you could press two! ... Then you could have a pure chain drive solution ... would be interesting to try both and see if there is any difference ...
Blimey, I hadn't realised how simple the Stokemonkey installation was. It's just a rear hub in the frame. Only drawback is the lack of freewheel, which dictates the rider keeping up with the motor all the time it's running, which I would find annoying.
On thinking about it, it would be difficult to incorporate a freewheel, so KISS.
On thinking about it, it would be difficult to incorporate a freewheel, so KISS.
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Yes. I think if I am going to use a hub motor it will be split chain with a fixed sprocket to drive the rear and a freewheel connected to the crank ...
Not sure that pressing the sprocket is going to be robust enough ... Dont think that is what the Germans have done ... but I'm still trying to figure that out ....
Just been looking at this thread on the German forum:
eBike mit Tongxin als Kettenantrieb - Seite 46
Seems to me that the fixed sprocket has been pressed and free wheel sprocket has been atached to an axel/bracket that screws into the six holes. Anyone agree? .... Also, has anyone thought to join the German forum. Does anyone participate? Perhaps I can buddy up with Herr Schwarzaldachzer or Herr Troubleshooter.. and get hold of some bits and pieces .. After all I have got a german made HPVelotechnik recumbent. Surely they will bend over backwards to help me? ...
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