About to rewind a hubmotor for a BMX wheel.

Mouse

1 mW
Joined
Jul 2, 2020
Messages
17
I'm making a BMX styled small framed ebike and am lacing what I think is a 1000W motor originally for a 26" wheel into a smaller 20" wheel.
I bought a broken burned out motor with the intention of rewinding rather than buying a new motor and taking it apart.
I'm planning of rewinding the hub with fewer turns to compensate for the smaller wheel which will need to spin faster and return it to the same speed / voltage etc. I have little to go on for this as the motor was burned out when I got it so have no idea how fast it spun as standard but assume it came from a 26" wheel.
Ratio of 26" wheel to 20" wheel is 0.77
Ratio of 7 turns to 6 turns is .85
Using something I found that says Turns * kv = Constant. these numbers are kind of close .

The motor was originally wound with,
7 turns of 8 strands of 0.5mm wire.
New spec idea,
6 turns of 9 strands of 0.5mm wire.

I've already laced the rim using paired spoke pattern rather than radial which should be stronger and looks good and I'm going to be rewinding the motor later in the week and would welcome any idea about rewinding for this sort of conversion.

IMG_20230516_183822_307.jpg
Shortest spokes I've ever seen.

IMG_20230516_190234_549.jpgIMG_20230516_193327_323.jpg
Paired spokes for some torsional strength.
 
Last edited:

calab

100 kW
Joined
Dec 10, 2013
Messages
1,506
There are lots of links showing you how to rewind a hub motor, it is quite tedious and time consuming but your in it for the hobby aspect.

What is your current plan to rewind the motor? Have you found the right wire and insulating paper?
 
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