Help?! Rear hub issue 500watt 8fun hub


New member
Local time
1:42 PM
Jul 10, 2022
Hey all,
Trying to get an older fat bike going and diagnosing my hub , the hall sensors and field wires light up the diagnostic tool when I rotate the tire backwards, no lights when I turn it forward.
I took the wheel off the bike, it rotates easy in reverse…there is resistance,no real cogging, rotating forward.
I’ve shorted the wires in pairs and definitely get cogging.
Hooked up to the controller there was no movement.
Any help would be appreciated


  • 7F98372C-2176-4284-A0D0-CD77B07B68B4.jpeg
    150.9 KB · Views: 98
Tell us what your starting point was.

Did it EVER work? Since you got it? Has the controller been changed, or disconnected?

There is a flowchart for determining correct phase and Halls, 36 possible combinations can be reduced to a much smaller number.

Have you removed the side covers, can you confirm this is a geared motor, and are you sure it is mounted in the correct orientation.? Sounds like rotation direction might be reversed. A geared hub, which this is likely to be, will rotate easily FORWARD, with some resistance when rotated BACKWARDS. The opposite of what you have.
Thanks for the reply!
New to ebikes, got this from a friend who road it hard.
It came to me in parts in a box!
It had the old controller,new controller, and a bunch of screws ,plastic bits, covers, wires two broken throttles,and a battery (48v 9ah) whew.
I’ve had the bike for a year, reading and watching videos on ebikes and repairing diagnosing issues.
I purchased a controller, throttle, motor diagnosing tool (seen in the picture in my first post). I’ve tested the new controller (it works) I’ve purchased a working throttle.
Testing the hub has been challenging.
I can’t seem to wrap my brain around what’s going on with the inside electronics.
The tester reads good hall sensors good motor windings going backwards, no reading going forward.
Is there a defective clutch?
Gears are shot?
Is there a special tool to remove the freewheel sprockets from the hub(to go over the bolts and connector?
Thanks again!
Thomas Grant
When you say "Forward", and "Backward", how, EXACTLY, are you determining which is which?

SFAIK, the readings you get are correct, if the directions are reversed.

What about the PHASE WIRES - the most important ones?

Why did your friend buy a NEW CONTROLLER? This is VERY important.

Have you charged, and tested the battery? This is critically important with such a long storage times. Could be a very expensive mistake.

Yes, there is a special tool, two different ones, in fact. Depends on whether you have a screw-on gear cluster, for which the standard bicycle tool will work, or a cassette gear cluster, in which case you need a special socket, in particular a deep-dish one.
Again thanks so much for taking an interest in my problem!
It appears there was water damage to the old controller…
I have determined forward as if the chain side of the hub were rotating as if the pedals were pulling the tire forward (sprocket’s on right side of bike).
I set the axle on a wheel stand (holding the axel from rotating)
I may find answers once I get the cluster off and break into the hub….
Just curious if anyone else had this issue?!
Battery is good!
I have 2other electric vehicles (fatty and scooter)
Tested battery on those.
Most of these you do not need to remove the gears to remove the side cover, I think.

IF you are connecting the phase wires on a new controller, getting them in the wrong order will produce the results you are seeing. IIRC, at least one combination will run correctly in all aspects, just rotational direction reversed.

You need a voltage meter to test the battery. "it works" is not AT ALL sufficient for a long-term stored battery. Need to find out what it SHOULD read, and this is not simple, and also an actual reading and hopefully you have the charger, or are ready to take the battery apart.