Electric Bikes - Internal gear hub with a hub motor?

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Saltydawg
12-02-07, 04:56 PM
So it seems like the best possible ebike motor would be one that has the benefits of the chain drive (using the bike gears) and also has the benefits of a hub motor (quiet, resistant to the elements, easy to install, etc).
How about a hub motor that is mounted on a rear hub that has internal gears? Would something like this be possible?
I'm sure there must be an obvious reason why this isn't already the most popular the most popular conversion to make an ebike, and I just don't know enough about it yet to see it.
Does anyone sell a rear wheel brushless hub motor conversion kit that has an internal geared hub?
http://en.wikipedia.org/wiki/Hub_gear
I would think a hub motor could be put on one of those just the same as any other hub, right?
I've seen a rear hub with an external cluster, but not internal gears. Common are front hubs and rear internal hubs.
JeanCoutu
12-02-07, 05:14 PM
http://sram.com/_media/techdocs/Sparc16V_Ins_EDFNlDkSv12_05.pdf
Sram Sparc is a 5 speed hubmotor, don't know if it's brush or brushless.
The motor part is singlespeed and geared.
Dahon Roo El is equipped with this thing
Abneycat
12-02-07, 05:40 PM
I don't know of any hub motor that uses multiple speeds aside from the Crystalyte dual speed series (which don't use gearing, rather a selectable stator setup). I've heard some fairly mixed reports about how well these dual speed motors work.
I recall the Sparc as well, but as JC says, it has an internal gear system like a Sturmey-Archer and so on, but the motor itself doesn't utilize that gearing. One of the big reasons is probably cost, both of these objects (geared motors and internal gear hubs) are expensive compared to their counterparts, dérailleurs and direct drive hubs, combining them together would likely make one *very* expensive piece of equipment.
In my opinion, something like this would probably be *great*, with high performance and low maintenance, if done right. But with the amount of complexity involved, it would have to be done *right*, and would cost dearly to do so.
Saltydawg
12-02-07, 05:48 PM
http://sram.com/_media/techdocs/Sparc16V_Ins_EDFNlDkSv12_05.pdf
Sram Sparc is a 5 speed hubmotor, don't know if it's brush or brushless.
The motor part is singlespeed and geared.
Dahon Roo El is equipped with this thing
The problem with that one is it's only 200 watts and 16 volts. That doesn't seem like enough power...
Does that motor use the bicycle's gears? I would think it would, but I can't really tell if they are only for pedalling or if the motor uses them too.
If that uses the bike's gears though, it would be perfect if it had enough power to move a heavier guy like me (220 pounds). Based on what I have been reading here, I think I need at least 500 watts (or more) and 36 volts (or more).
It's good to know that these things do exist though. Maybe there is one out there that has the power requirements...
Saltydawg
12-02-07, 05:53 PM
I don't know of any hub motor that uses multiple speeds aside from the Crystalyte dual speed series (which don't use gearing, rather a selectable stator setup). I've heard some fairly mixed reports about how well these dual speed motors work.
I recall the Sparc as well, but as JC says, it has an internal gear system like a Sturmey-Archer and so on, but the motor itself doesn't utilize that gearing. One of the big reasons is probably cost, both of these objects (geared motors and internal gear hubs) are expensive compared to their counterparts, dérailleurs and direct drive hubs, combining them together would likely make one *very* expensive piece of equipment.
In my opinion, something like this would probably be *great*, with high performance and low maintenance, if done right. But with the amount of complexity involved, it would have to be done *right*, and would cost dearly to do so.
Oh, okay, so the motor doesn't use the gears then. Well that sucks...
It would probably cost a lot to make something like this at first. But as mroe and more people start buying/making them, they will become cheaper and cheaper.
It's too bad nobody is making these yet. It seems like the logical evolution for ebikes...
Abneycat
12-02-07, 06:01 PM
The problem with that one is it's only 200 watts and 16 volts. That doesn't seem like enough power...
Does that motor use the bicycle's gears? I would think it would, but I can't really tell if they are only for pedalling or if the motor uses them too.
If that uses the bike's gears though, it would be perfect if it had enough power to move a heavier guy like me (220 pounds). Based on what I have been reading here, I think I need at least 500 watts (or more) and 36 volts (or more).
It's good to know that these things do exist though. Maybe there is one out there that has the power requirements...
It does not. It has gears of its own that you can use as the cyclist, but the motor itself is a single speed geared unit. The Sparc is also a low power unit, its a system thats geared towards the cyclist crowd rather than the e-biker, so its built around helping out with headwinds and hills rather than powering you around on its own.
As for the 500w thing, thats entirely subjective to the motor being used.
Lowell_
12-02-07, 10:44 PM
So it seems like the best possible ebike motor would be one that has the benefits of the chain drive (using the bike gears) and also has the benefits of a hub motor (quiet, resistant to the elements, easy to install, etc).
How about a hub motor that is mounted on a rear hub that has internal gears? Would something like this be possible?
I'm sure there must be an obvious reason why this isn't already the most popular the most popular conversion to make an ebike, and I just don't know enough about it yet to see it.
Does anyone sell a rear wheel brushless hub motor conversion kit that has an internal geared hub?
http://en.wikipedia.org/wiki/Hub_gear
I would think a hub motor could be put on one of those just the same as any other hub, right?
It can certainly be done, but I don't know if there's enough demand for such a system. The Puma gear reduction hub motor seems to have gone through several design changes so far without any kind widespread distribution, but hopefully they will get it right soon. If that catches on, it would be natural for a multi speed model to follow...
The designs are out there......
http://www.diro-konstruktion.de/change-over_gear.html
Miles
JeanCoutu
12-03-07, 10:54 PM
The problem with that one is it's only 200 watts and 16 volts. That doesn't seem like enough power...
I recall reading reports about the first gen ones, 12v, and it seems they were anemic. The new 16v ones are likely better, if only because they can actually give assist up to the 20mph max speed. But there it is, the only gear hub with hub motor that can be purchased, to my knowledge.
But there it is, the only gear hub with hub motor that can be purchased, to my knowledge.
Keep in mind that it is a gear hub with a hubmotor but it (apparently*) doesn't fit the description in post#1, which was a hubmotor that takes advantage of the multispeed gearing in an internal gearhub.
*see post #7