Failed hub clutch, need 87.8mm 88mm clutch /36T 47.5mm gear assembly for new 500W hub motor

[EV_Ron]

Hello endless sphere,

I bought a brand new, 500W rear hub motor this past December (still in warranty) from a well known seller in the U.S..

The problem is, after 40-50 miles, the hub case and wheel stopped turning, but I can hear the internals ("rotor"/"stator"?) spin.

The seller tech support said the cause this time was probably the SW900 LCD display and to buy a new one. I first complained about this display back in February. Then, the problem was, with display OFF, throttle and PAS would still operate the motor. This occurs both with SW900 and LED 810, and the clutch failure occurred with the LED 810 so, I don't see how it could be the LCD display and I asked them to explain... (I also poorly indicated my frustration, and they haven't responded.)

Up until the time of failure, the motor performed well both with the LED 810 & SW900, with more power than my Cute Q100, and probably more than my Q100H (stolen 5 years ago). I see 300-400W typically, and 700-900W during acceleration in PAS 3/4/5 or with full throttle. No other problems except the noise from the new motor, a whiny whir, similar to but about 3x louder than a Q100.

After hours of searching here, it seems the clutch has failed or at least locked up. At least six times I've tried d8veh's to "tangentially hit the tire forward" but had minimal success. By that I mean, a couple times- with the slightest throttle- the hub casing & wheel will now turn up to maybe 1mph, but at 2-3 mph it begins to groan a little bit and then the internal motor continues to spin, but it must overrun the clutch which stops engaging the 47.5mm gears & hub case. (I don't exactly know how this Sprague clutch works, or if the 87.8mm disc is the clutch or just the gear carrier. Is the large disc the clutch?)

I'm looking for ideas on a source for the larger clutch & gears spec'd below. There are no clutch-gear assemblies on their webpage, nothing on EMV, eBay, nor aliexpress. I did contact the seller but no resolution, yet. After 3 days now, I'd say they're ignoring me.

I opened the case and measured the clutch & gears multiple times. Everything looks perfectly normal:
I've searched all the dimensions numbers but nothing comes up for an assembly.
I've read many geared hub gear/clutch failure threads on E-S, but none discuss clutch/gears with these larger components:

Component measurements

1. Nylon gear diam. 47.5 mm
That's exactly 1.25x larger than the available 38mm nylon gears out there. I can find 47.5 mm gears on eBay for Bafang 8Fun motors, so it must be a thing, but there are no 47.5 mm gear & clutch assemblies and 87.8mm is not mentioned anywhere as a clutch diameter...or anything rise for that matter. I even checked 3-29/64" & 3-1/2" clutch assemblies (nearest 87.8mm equivalent), but nothing.

2. Nylon Gear thickness x 13.20 thick (typical gears are 12mm).

3. Clutch disc diameter x 87.8 mm
This is also 1.25x larger than all the 70mm clutches out there. Nothing is listed on eBay nor aliexpress.

4. Clutch disk thickness 10.2 mm
Stamped LM2012131

Having read that it's a closely guarded business secret about the manufacturer for this seller's motors (I've read MAC, MAC knockoff) does anybody know what gear set would work and a source? I've searched 10 different ways but the larger 87.8mm spec clutch assy. is not discussed anywhere that I could find, and I've checked E-S, ebike reviews, internet, seller's blog, YouTube.

Thanks.


More info (3-4 April):

I have maybe 40-50 miles on the motor, have only used it about 25 times for about 1-1/2 to 2-1/2 miles at maybe 10-12 mph, usually in PAS 2, sometimes 3. I may possibly use a more aggressive mix of throttle and stopping and starting pedaling, and use of brakes / motor cutout. I use the bike only in a big, flat, grass park in back of where I live. The ground is not rough, but it's not a putting surface, either. There are no roots, no ditches, no drops, and no jumps. I'm only 165, bike weighs about 50#, dual suspension.

From what I've read, it seems repetitive throttle/PAS on-off usage may be too rough for the clutch, which I guess is designed for constant speed?. I expect each on/off cycle has to repeatedly re-engage the clutch. I have not opened & inspected the clutch. The bike is dual suspension so there should be relatively little rotational impact due to wheels hitting anything.

I used the Q100 and Q100H the same way and they never failed (only the KU63/65 controller failed after 8 years, due to an internal 5V power supply, which was the reason for my upgrade.)

I did not know the winding count on this motor when I bought it and should have checked or asked, since I've read higher wind counts are for slower speeds requiring more torque like I need. Checking, I now see the spec'd RPM is 300 on their website, probably too fast for my purposes, but at this time, the clutch seems to be the component that failed, not the motor windings. And, the motor case always runs below 95F (cooler than a Q100) and the 500W controller runs at about 85F. I nearly always pedal with the motor adding maybe 100-150W.

The symptoms are no hub rotation even though the motor is whirring away inside. With throttle or PAS, the rotor(?) spins inside the case & sounds almost like normal, except the hub/casing does not turn. (4 Apr 22 update: with the motor and hub off the bike, if I connect the motor cable and turn the throttle, the axle turns just barely maybe 1/8 turn and when I stop the throttle the actual turns backwards about 1/8 turn (reverse EMF I guess?). If I turn the pedals a little faster I get a 1/4 turn of the axle, but there's minimal force.) There is no grinding or other noise, so I first assumed the gears were ok, and while waiting for an ebikeling response I opened the case: both nylon and metal gears appear perfect. (I do notice that most of the grease has piled up in 2 or 3 locations, so, the gear teeth surfaces apparently need very little grease.)

I'm using this motor with a "refurbished" 500W 36/48V ebikeling controller (never again) , at 41V down to 35V, I see 200-400W mostly, 550-750W occasionally and only momentarily at acceleration. I use both brake cutout (2-pin) & and PAS a lot and like them a lot.

Based on oneYouTube video, I just opened the case and after measuring the gears/clutch, I checked and everything turns easily, it's just that the motor seems to slip past the clutch. I tapped the axle twice and the silver clutch 5-6x with a plastic-headed mallet...I'd say 15-20# force? I...then powered up the motor and there is no change... hub case does not turn.

 

[EV_Ron]

Son of a gun, they round up. 88mm clutch.

https://m.aliexpress.com/item/32953566014.html?spm=a2g0n.productlist.0.0.5a98FCVuFCVudy&browser_id=04ca1be3004740c089db6b268d839171&aff_trace_key=&aff_platform=msite&m_page_id=cbuegkqw8zwcaaw41800026f8a82537552a29efd06&gclid=
After all that.

Also found this, for Bafang SWX02 / RM G06 fatbike/ snow bike motor but 11mm thick nylon gears. I need 13.2 mm.
https://www.greenbikekit.com/rm-g06-snowbike-fatbike-swx02-motor-clutch.html

 

[EV_Ron]

Assembly/reassembly/testing

Having found that this seller's top notch customer support is woeful at best, I searched longer and found that the Bafang SWXO2/G060 clutch assembly comprises the 88 mm clutch w/ 48mm/13.5mm gears. So it's the same as used on this 500 W motor. $42 free shipping, 2 weeks. Three sellers on aliexpress or eBay only. 47.5mm gears, 88MM CLUTCH: BF RM-G060. Gears 13.5mm thick for 500W, 11mm for 750W gear 36T.
https://m.aliexpress.com/item/1005001530835342.html

EBay $45 TopBikeKit
https://www.ebay.com/itm/175158065220

This is the groaning sound once I was able to get the clutch partially free ...no video upload.

Then, I went out to take off the cover again and attempt to remove the clutch assembly... by force.

Whereas most Bafang videos show the clutch comes right off in the case during removal, (and these people have 2-5000 kms on their motors) mine required a 16 inch crowbar on either side of the clutch, and at least 12 good hits with a hammer on the crowbar at about the 12 inch mark to coax the clutch shaft off the key motor shaft keyway. The key comes out of the keyway easily, and went back in easily. I later only had to lightly tap the clutch back onto the shaft.

Everything looks normal- the shaft looks good, the gears are fine, the clutch looks fine, the gear teeth inside the case are perfect, there is no debris, just clean white grease.


I removed the right, freewheel section & right cover of the motor and the motor looks fine everything spins freely. No burning smell, nothing unusual. Both bearings inside the motor case shell turn freely. The clutch turns freely in the forward direction but is locked in the back direction which I think is normal?. Magnets are all secure.

I do notice that when reassembled (same as before, too), the motor shaft turns freely in the forward direction but in the reverse direction there is 5 to 10 times more resistance. It turns in reverse but doesn't want to spin freely like in the forward direction. I have to go find what d8veh said about that.

Having found no problems with the motor visually, I reassembled and reinstalled on the bike.

Result: the bike did the exact same thing as the first time the motor slipped the clutch (or whatever it's doing): it went about 10 feet in PAS 1, got to maybe 3 mph, but this time it groaned first and then slipped the clutch (before it was just normal, hub-motor-whining). Same as before: I could turn the throttle or pedal and use PAS, and I could hear the motor spinning inside the case but the case didn't turn.

What I don't understand is why the entire motor groans between 2-4 mph like it does , which it never did before; I'm assuming the clutch.
Video motor & after reassembly. (Will edit once see if videos can be uploaded. Found it- videos ended 2017. Will see about uploading to YouTube.)

I hate to give the sellers name (on 2d thought, I don't mind at all), but if there are any others out there who have used the eBikeling 500W motor, have you ever heard this groaning noise from your motor? Or is there anybody else with a 500 watt motor or any hub motor, and have you ever heard this groaning noise?

 

[Valopallo]

Hello. I might have the exact same motor at front (a chinese copy rather than the original 8FUN/Bafang.) My gearing went bad and I bought this as a replacement. https://www.aliexpress.com/item/32971035170.html?spm=a2g0o.order_list.0.0.21ef1802AzsRvl
Hope this helps.

PS: Don't mean to hijack your topic but if it does not hurt to ask anyway; do you or anyone else have the coil winding schematic for this 18 slot motor? Thanks.

 

[EV_Ron]

Thanks for your response. I have the 500W motor and need the 88m clutch with 47.5mm gears. But, same seller TopBikeKit, who also sells on eBay.

Did you attempt to use ebikeling's warranty?

Don't think you hijacked at all...trying to troubleshoot and find parts.

No schematics. Will I need them soon? How old is your motor?

 

[EV_Ron]

Disassembled motor a third time. Interesting to note that, unlike the first time when I just took the motor/clutch combo out, and the 2d disassembly when I decided to intentionally force the clutch off the shaft with pry bar and hammer, this time the clutch and gear assembly simply dropped off like in ALL the videos I watched!


Ran the motor independent from its clutch, bearings and casing/freewheel, just holding the axle flats in a vice. Ran normally, mostly silent, full torque - I couldn't hold it from turning with my hands even just barely turning the throttle. It was still a little glitchy but quiet by itself; IOW, of the 20 times I ran it up and down in RPM, it stuck or bucked a couple times. I disconnected and reconnected several connectors, particularly the throttle connector. Then, reassembled all, and tested it again with the wheel off the bike- still ran normally. So, reinstalled on the bike, and it ran normally with rear wheel off the floor, perhaps quieter than before when new.

Then, ran it full out in field, and with new settings in display & controller- 93 magnets and 16" wheel- the motor runs normally, 9-10 mph in PAS 5, with me pedaling low to medium, nearly the same with throttle. This is essentially the same as my calculated speed for 2 laps: 4000' in 5 minutes= 9 mph.
And, that is very strange because it's actually got 20 magnets -because I counted them- mounted in a 26" wheel. But, that parameter combination in the display shows 30-32 mph full speed, and there was no way. I'm wondering if it's actually a high wind count, high torque, low speed motor...which is really what I wanted in the first place.

I don't know exactly what the problem was and what "fixed" it... because at the end I dropped the motor once from about 2' as I went to reinstall it and it slipped. It hit the end of the axle on the right side - maybe that realigned something? I just don't get it.

Will update if it fails again.

 

[Bullfrog]

The groaning noise may be caused by your controller sending bad info to your motor...perhaps one of the hall sensor wires was not connected completely. You may have solved the problem by accident when unplugging and plugging in the connectors.

Just my best guess .