The biggest hub motor I have ever seen...

[fechter]

That's a great find!

While you're gluing magnets, you could upgrade them to NdFeB. It would look stock on the outside

The pinion shaft does look like a weak point, but seems like it wouldn't be too hard to improve on the basic design. I like the high reduction ratio.

Not freewheeling I take it. This would allow regen in that case. I bet it's terrible to pedal with a dead battery though.

[methods]

Not freewheeling I take it. This would allow regen in that case. I bet it's terrible to pedal with a dead battery though.

It actually has a freewheel inside - the "black tube" (see first post) - so no problems with freewheeling.

-methods

[liveforphysics]

That's a great find!

While you're gluing magnets, you could upgrade them to NdFeB. It would look stock on the outside

The pinion shaft does look like a weak point, but seems like it wouldn't be too hard to improve on the basic design. I like the high reduction ratio.

Not freewheeling I take it. This would allow regen in that case. I bet it's terrible to pedal with a dead battery though.

Going from ceramic to Nd would cut the speed of the motor by around 4x or more. Jumping the voltage up to compensate is not going to fly with the brush arcing.

[madact]

madact,
Those are called geared hubmotors. They have pancake outrunners inside spinning a small gear, which turns planetary gears connected to a big ring gear on the exterior shell.

I know, I've seen em... but the ones I've seen seem to have pretty small gears in em - the outer ring of the planetary system is nothing like on the scale of this thing.

[fechter]

Going from ceramic to Nd would cut the speed of the motor by around 4x or more. Jumping the voltage up to compensate is not going to fly with the brush arcing.

I'm not sure if it would be that much. I suppose it depends on how good the magnets are. Yes, you'd have to increase the voltage to compensate, but brush arcing is not just voltage dependent. I've seen plenty of brushed motors running 90V or more as long as the current isn't too high. I did a similar thing on my old Zappy. I rewound the motor to compensate for part of it and doubled the voltage. The brushes were about the only thing I didn't have problems with.

Hmm... I suppose that's a good excuse to make it brushless.

Oh, and I missed the part about the freewheel. That makes much more sense now.