Getting the wheel apart

[drsolly]

Problem in my motor wheel; it will turn one way, but is totally jammed the other way. It's a 250 watt geared hub. I suspect gear damage.

But the first problem is, I can't get it apart to have a look inside. If I try to take the cassette off, the only way I can see is by turning it via the two small hoes about a centimeter from the center. And I can't turn in, even if I whack it with a hammer-and-screwdriver.



If I try to get in from the other side, there's a drum brake screwed on. To remove it, I'd have to turn it anti-clockwise (I think), but I don't have a tool that will get it off, and the old hammer-and-screwdriver on the two 1-cm holes in it, won't budge it either.

WD40 hasn't helped.



I'm a newbie at this level of bike repair. Could anyone suggest A) which side do I really need to get off, and B) how to do that first stage of dismantling? Is there a tool I need to get?

Thanks.

 

[Deleted member 4366]

If you undo those 6 screws, the whole side will come off with rhe gears still attached. You'll have to remove the nut inside the gears first if you want to get at the internal gears. Once you've removed that side, the guts of the motor can be rapped out of the housing by hitting the axle on the other side with a soft mallet. No need to touch the brake except that you jave to remove the nut on that sife if you want to take the guts out. You don't need to remove the guts to service the clutch and internal gears, but if it moves OK one way then it's more likely that a magnet is jammed or something like that.

 

[drsolly]

Thanks, that worked!



So, here's the inside, and it's obvious now that the problem is the gears. The steel outer gear looks OK, I can clear out the bits of nylon gear from the inside, but the next questions are:

1) how do I pull the gear wheels off their spindles? I removed the circlip from one of them, but I think there's more to do before I can get it off.

2) The motor says "8fun" inside, but I'm guessing that these gears are fairly standard. Where can I source a set of gears? Would these do the trick?
http://em3ev.com/store/index.php?route=product/product&path=41&product_id=109

 

[shemozzle999]

Thanks, that worked!

View attachment 8362

So, here's the inside, and it's obvious now that the problem is the gears. The steel outer gear looks OK, I can clear out the bits of nylon gear from the inside, but the next questions are:

1) how do I pull the gear wheels off their spindles? I removed the circlip from one of them, but I think there's more to do before I can get it off.

2) The motor says "8fun" inside, but I'm guessing that these gears are fairly standard. Where can I source a set of gears? Would these do the trick?
http://em3ev.com/store/index.php?route=product/product&path=41&product_id=109

Available from here:

http://www.aliexpress.com/store/product/planetry-gear-speed-reduction-system/612941_621839379.html

 

[trex]

or ring Hatti at Woosh, get a new clutch unit.

 

[drsolly]

Aliexpress looks good, cost £20 inc. P&P.

Thanks, I've emailed Hatti.

Meanwhile ... I have a similar motor that has bad bearings. I took it apart, took out the planetary, and fitted it to the motor, I think the replacement planetary is good enough for test purposes. I'll finish putting everything together tomorrow, and I'll give it a test.

Thanks to everyone for all the help.

 

[Deleted member 4366]

Do you know what caused the motor to end up like that?

 

[drsolly]

Maybe.

It's a 24v motor. I got a new controller from em3ev, but that was stuttering, and the problem turned out to be that although you can program the LVC to be 25v, it is still somewhat higher than that. So when I ran it at 8s, it was OK while the voltage was above 32 or so, but stuttered when it got below that.

So I thought, OK, let's try it at 12s, 50v.

The controller was fine. But I was putting maybe 40 amps through the motor, and as I was testing it on a local steep hill, the motor failed, and I pedalled home.

So I think I just put too much stress on the gears. Or maybe it got very hot in there? I felt the motor, it wasn't even warm.

Paul at em3ev has told me how to mod the controller so it'll be OK at 24v. So when the necessary resistors arrive, I'll do that mod, and run the bike at 8s.

 

[Deleted member 4366]

I guess that you learnt the hard way that you can't put 40 amps through one of those motors. The combination of heat and torque will shred the gears as you found out. 22 amps is about as high as you should go, and even then, you need an understanding of how to avoid the motor heating up.

 

[trex]

this case will remind self builders to go easy on the Amps. Those nylon teeth will bend and heat up - it's cheaper on the long run to buy a 350W motor where a 250W would do. Also, think of the crank drives, they have helical steel gear mesh, a lot stronger than the straight cut on many geared hub motors.

 

[Woosh]

Aliexpress looks good, cost £20 inc. P&P.

Thanks, I've emailed Hatti.

Meanwhile ... I have a similar motor that has bad bearings. I took it apart, took out the planetary, and fitted it to the motor, I think the replacement planetary is good enough for test purposes. I'll finish putting everything together tomorrow, and I'll give it a test.

Thanks to everyone for all the help.

Yes, we can help with these.
The cost is £10 plus £3 carriage.
Hatti, Woosh Bikes

 

[drsolly]

I'm using the Infineon controller, and that should let me limit the amps. When I put this back on the road, I certainly will be limiting the amps. And I'll only use 8S.

You can put that picture into the forum Chamber of Horrors!

 

[drsolly]

New part bought from Hatti, thanks to everyone for their help.

 

[drsolly]

The bike is back in action; I took it for a test run today. It took me ages to work out how to reassemble the drum brake properly (hint, there's two washers that go inside it). Andgetting the derailleurs set correctly is always something I find difficult.

I'm running it on 10S Lipo, because at 8S, the Infineon controller keeps hitting LVC. The vendor told me about a mod (changing a resistor) but that doesn't seem to have worked.