Bafang Bbs01 unusual fault

[Woosh]

we may have replaced a couple of freewheels in 3 years, they were on well used BBSes.
As you said, it could well be a manufacturing defect.
Can you claim on warranty?

After checking, there was only one case and the damage is in the thread, not the pawls. When the customer pedals, the spline moves although the pawls work.

here is a picture:

 

[jarob10]

Thanks for the feedback, sounds like I've just been really unlucky then.

[QUOTE="Can you claim on warranty?"
[/QUOTE]

Not really worth it for £7.50 in parts.

Although I've had to order a replacement rubber (bonded) seal that had to be destroyed to allow the shaft to be disassembled. - only £15 though.

I'm intrigued to find out the OP's freewheel failure mode

 

[Croxden]

Yes, a complete list of every expense, including dealer charges, would be very useful for people to assess the cost of long-term ownership.

The bike around £4600.00, Rohloff oil £35.00 (approx for two lots, third in the post), brake pads £17.49, service, two sprockets & chain £130.00.

That is upto the 8000 plus miles when the chain first started to slip.
I expect it to continue in a similar manor. Any other works undertaken by OnBike was a warranty issue, namely replacement Intuvia display and a seized piston on a brake.

 

[Woosh]

thank you croxden.

 

[Deleted member 4366]

The bike around £4600.00, Rohloff oil £35.00 (approx for two lots, third in the post), brake pads £17.49, service, two sprockets & chain £130.00.

That is upto the 8000 plus miles when the chain first started to slip.
I expect it to continue in a similar manor. Any other works undertaken by OnBike was a warranty issue, namely replacement Intuvia display and a seized piston on a brake.

Assuming a residual value of £2500 (might be a bit optimistic), that works out at 28.5P per mile.

 

[Croxden]

Assuming a residual value of £2500 (might be a bit optimistic), that works out at 28.5P per mile.

The reason I bought it was that I wanted it and could afford it. I think I'm getting my monies worth.

 

[jarob10]

I would say that it's your clutch that's jammed. You can buy replacements. I thought Woosh were selling them, otherwise from here:

http://www.greenbikekit.com/bafang-8fun-mid-crank-motor-clutch-for-replacement.html

Here's hoe to dismantle the shaft from the motor:

https://endless-sphere.com/forums/viewtopic.php?f=28&t=65711

UPDATE: pawls from dt Swiss 'onyx' free hub fitted and working.

The onyx pawls are a different shape to the originals, however they appear a better 'fit' in the pawl carrier - side on they fill the carrier chamber more, and are physically wider which should reduce the stress on the splines. See attached pictures and compare to wooshes on post #7

 

[Woosh]

I am glad that you got it sorted.
I was a bit puzzled when I looked at the picture of the old worn pawls. They seem a bit thin. On the new picture, the difference is quite clear cut. The pawls on the GSM are in between the top and bottom pawls and black, not silver.
Good find though.

 

[Fordulike]

UPDATE: pawls from dt Swiss 'onyx' free hub fitted and working.

The onyx pawls are a different shape to the originals, however they appear a better 'fit' in the pawl carrier - side on they fill the carrier chamber more, and are physically wider which should reduce the stress on the splines. See attached pictures and compare to wooshes on post #7View attachment 18792View attachment 18793View attachment 18794

How much grease and what type was on the original mechanism? I think the pawls constantly rub on the outer bit whilst freewheeling, so manufacturers must use something to reduce friction wear.

 

[jarob10]

How much grease and what type was on the original mechanism? I think the pawls constantly rub on the outer bit whilst freewheeling, so manufacturers must use something to reduce friction wear.

No evidence of any lubrication at all during the initial stripdown. I applied a smear of engine oil to the female splines during rebuild.

 

[jarob10]

Another drive failure in my spare bbs01b (motor #2). This motor was installed exactly as received from an aliexpress supplier, with no mods done other than applying mobilgrease 28 to the large gear.

Following stripdown the following was observed:

1.
Splines damaged at two positions, one area shown below at 12 o clock. The rest of the splines are in a sorry state after only 1500miles


2. Pawl retaining ring had rotated on the pawl carrier. The indent feature had failed to stop rotation of the ring. I was able to reinstate a suitable indent by peening over with a screwdriver. The ring gap had also opened up during running - see picture below (old pawl carrier on left, new unused carrier on right)


3. Pawl wear was minimal when comparing against new unused pawls.


Unfortunately, unlike my experience on motor #1 earlier this year, I was unable to upgrade to the dt-swiss onyx pawls as they wouldn't work on this motor #2. The approach angle of pawl to spline was too shallow leading to occasional drive slippage. I have a new OEM pawl assembly which seems to operates ok though. I will rebuild with a tiny blob.of grease at each pawl pivot, along with a smear of engine oil over the splines.
My mistake - once I'd put the onyx pawls in the right way around, they worked perfectly

Good news is I have enough spares to get up & running again, but am unsure why I'm experiencing such problems. I wonder if my SPD pedals are transmitting too much human torque through the pawls? I'm running a 52t front sprocket with 11-32 at the back, and maintain a cadence of 70rpm to match the motors sweet spot.

Best theory at the moment is the failure of the pawl spring retaining ring feature being the root cause - easily resolved by peening over with a screwdriver & hammer