Opening a hub motor - FAQ

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roadrider   1 µW

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Re: Opening a hub motor - FAQ

Post by roadrider » Mar 08 2016 10:34am


I have the same hub motor (from and I'have some trouble after remounting it.

I did open the motor, clean it a bit and after remounting the to covers, the motor is bent. I insist on the fact that it is not a spoke/rim issue, the whole motor oscillates when I turn the wheel.

I can't figure out what I have done wrong.

Is it possible that I've bent the metal of the motor when I've opened it ?

I hope I'll find a solution because now I have to use my old diesel car...

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amberwolf   100 GW

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Re: Opening a hub motor - FAQ

Post by amberwolf » Mar 08 2016 2:03pm

Without pics or diagrams or a better description, I'm unsure of your exact problem, but if it's just the covers, one of two common things could cause problems:

--covers are not always made perfectly, so if they are installed in other than the original rotation orientation, (using different boltholes to the sockets on the rotor than before), they may be offset so the wheel doesn't have the same offset around that it did before.

--covers are not always symmetrical, so if installed on the wrong sides, the wheel may not work like it should.

Unless extreme force was used it's unlikely the metal of anythign would actually bend to a noticeable degree; the same applies to bearing damage.

ThierryGTLTS   1 W

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Re: Opening a hub motor - FAQ

Post by ThierryGTLTS » Nov 08 2019 1:02pm

How to open A Q100C CST motor, after having removed the 6 screws if it is blocked by oxidation.

Here I speak about the BLDC motor to have access to the windings, the cassette cap side is already removed, and the inside block is out of the main alu cage .


jerome_speedy   10 mW

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Re: Opening a hub motor - FAQ

Post by jerome_speedy » Mar 26 2020 10:46am

Hi all,

I add my own question here because I bought a while ago a 2nd hand BLDC hub motor on the french equivalent of craigslist. My first tests showed that the motor will run on some occasions (I haven't figured out which ones yet, the errors were not repeatable if I recall correctly).

Now that I have time on my hands (with the covid19 pandemy !), I decided it was time for me to open the hub motor. Problem is there is no visible screws on either sides.

Side 1:

Side 2

I tried removing the flask by hitting the axle with a wooden mallet, nothing moved (I opened successfully several RH205 and a Golden Motor in the past, thanks to the info on these forums). I noticed two notches that I thought could be used to unscrew the flask (supposing the flask is threaded).

I built a tool exactly for that, copied from the tool to change the discs on the grinders, but managed to bend its arms when I applied pressure while trying to unscrew the flask.

Tool View 1

Tool View 2

I'm out of ideas as to how I can possibly open non destructively that hub motor. Since I know a lot of such chinese motors were sold and no kind of maintenance was expected, I simply think that the manufacturer might have permanently sealed it.

If anyone smarter than me (and I know there are a lot such people here) can give me some advice, I'd be grateful :)

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motomech   1 GW

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Re: Opening a hub motor - FAQ

Post by motomech » Mar 26 2020 2:33pm

You need a better (bigger and stronger) tool. Here are some examples;


Use the flat plate steel in the second pic and instead of doing that bad welding, use bolts and nuts to make the "nubs" that fit in the indent holes. If the side-cover(Flask is something else in english) will still not come free, gently heat around the outer edge with propane torch. It helps to have someone stand on the wheel.
"Lefty loosey" of course and good luck.

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/10Ah Multistar Lipo rear 4Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, Crazy Bobs run ghetto tubeless. 25 mph. Mean Well HLG-320H-54A ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 14S LiPoly elifebike 9-FET 20A controller. 23 MPH. ... 4#p1378484

jerome_speedy   10 mW

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Re: Opening a hub motor - FAQ

Post by jerome_speedy » Mar 27 2020 2:45am

Thanks for your answer, momotech.

Alas, I can't build a strong tool since most stores are closed at the moment due to the crisis. I saw an adjustable wrench on Amazon: ... YTOH&psc=1
that I will probably buy. Means I'll have to wait some more I'm afraid. (also thanks for the wrong use of "flask", I figured I saw that word used like that on endless-sphere but no !)

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