Is this a Brose design fault ?

outerlimits

E*POWAH BOSS
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Feb 3, 2018
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Or am I missing something?

I have had trouble where the chain would rotate when backpedaling. This is not good as it supposed to freewheel independent.
Pulled off the crank arm and there is a very small gap that is quite deep that had collected grit and sand ect. This was locking the chainwherl to the crank. The water must also gather in there and sit on a bearing seal. So this would make the area constantly wet.
Am I missing a seal ?
A seal brought forward would stop crap getting in there.

Whenever I wash my bike or it gets wet, I will lay the drive side down so water ect drains from this area.

41A661FF-81A1-4B9E-9BC4-91F44FF84DAB.jpeg
 

outerlimits

E*POWAH BOSS
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Very interesting!
I think I'd be on the manufacturer with these great pics and ask them, or at least start with the dealer.
What bike is it?
It’s a 2018 Turbo Levo.
I managed to get a sewing needle in there to dig out all the crap. It’s only got to be about 0.25mm gap and would be 8-10mm deep from what I gather.
There would be an outer bearing supporting the chain ring outer and an inner bearing supporting the crank arm shaft.
Bit like a small shaft inside a pipe.
 

outerlimits

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Why would someone design something with such a void to gather dirt and moisture ?
It’s really noticeable, blind Freddy could see it. Surely Brose are aware of it.
 

Kaelidoz

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Apr 29, 2018
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Why would someone design something with such a void to gather dirt and moisture ?
It’s really noticeable, blind Freddy could see it. Surely Brose are aware of it.

I've seen worse water ingress/debris ! Drilling holes in my Levo! - EMTB Forums

If you could to compare that would be great.
They crank on yours would freewheel back I would assume. Wonder if it’s sealed

I need to learn how to remove mine on the Haibike with Yamaha PW. I'll check if I see a seal and if there are any debris in there. Still freewheel backward without resistance tho (bike's 4 months old).
 
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outerlimits

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I've seen worse water ingress/debris ! Drilling holes in my Levo! - EMTB Forums
On my 2018 alloy frame the drain hole ain’t that big. It is central and internally is surrounded by the internal webbing brace. The water therefore has to reach 2mm before it drains. That creates a lot of pooling water that attracts dust in the dry and turns it to mud.
I make sure hole is not blocked after washing, and remove the covers to clean periodically if needed.
 

ccrdave

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I had the same problem, pedals turning backwards was moving the chain and was quite stiff but only for a few turns and it then went back to normal.
I will take the chainring off and have a look
 

outerlimits

E*POWAH BOSS
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Feb 3, 2018
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Yes you are missing a seal...look at mine...
Looks like a definite gap there to me. It’s hard to tell in that photo however.

Looking at these tear down pics, does not appear to be anything stopping moisture getting into the area of the sprag clutch.

87D8CD6F-CB7F-4DF2-9543-9F7010D02D8C.jpeg


35EC8F57-B3FC-4835-9ACF-C2608C396872.jpeg


E2F6E2CB-D7F3-4E0C-BD63-B8C6841D2419.jpeg
 
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Oldmanlevo

Member
Sep 1, 2018
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I will not be opening up my motor system till later this fall but I used a small scribe and the gray ring just inside the nut and outside the "bolt" rubber, which leads me to believe it's some kind of shaft seal...
hhhmmm
 

Donnie797

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Jul 2, 2018
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Bobtech

New Member
Dec 13, 2018
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I would assume that there is an internal seal, but who knows. Anyway, I plan to put on an o-ring for sealing, backed by a plastic ring that is in contact with the crank arm. The oring is 23.52x1.78. The plastic ring is from a Race Face crank, OD 29.2, ID24.2, thickness 1mm.

DSC_0874.JPG
 

outerlimits

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I would assume that there is an internal seal, but who knows. Anyway, I plan to put on an o-ring for sealing, backed by a plastic ring that is in contact with the crank arm. The oring is 23.52x1.78. The plastic ring is from a Race Face crank, OD 29.2, ID24.2, thickness 1mm.

View attachment 8783
I believe too much wear will occur on your O-rings for it to be any use.
I think if the inner shaft was made smaller in diameter or outer larger it would increase the gap between the inner and outer shafts, and would solve some problems. The small gap now allows tiny rocks, moisture and mud to get trapped and therefore affect the sealing of the bearings. A larger gap would allow debris and moisture to escape more freely, and would not affect bearing seal performance as much.
Perhaps @Specialized Rider Care could take this up with Brose ?
 

Bobtech

New Member
Dec 13, 2018
5
3
Norway
Good points. Of course the actual wear is unknown. But note that there is no movement between these parts as long as the crank arm (pedal) and spider (chainring) is moving together, as they will normally do. And when the crank arm rotates it now only cause wear on the plastic ring and the inner diameter of the o-ring. The side of the o-ring is not wearing. Thanks to the odometer on the bike I will be able to track mileage and I will inspect the o-ring as the time goes. We can also change o-ring material to be more resistance to wear. The current situation without o-ring allows water from a garden hose to accelererate towards the umknown internals. Please do let me know if you have any thoughs regarding this add would make the situation worse.
 

outerlimits

E*POWAH BOSS
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Feb 3, 2018
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Australia
Good points. Of course the actual wear is unknown. But note that there is no movement between these parts as long as the crank arm (pedal) and spider (chainring) is moving together, as they will normally do. And when the crank arm rotates it now only cause wear on the plastic ring and the inner diameter of the o-ring. The side of the o-ring is not wearing. Thanks to the odometer on the bike I will be able to track mileage and I will inspect the o-ring as the time goes. We can also change o-ring material to be more resistance to wear. The current situation without o-ring allows water from a garden hose to accelererate towards the umknown internals. Please do let me know if you have any thoughs regarding this add would make the situation worse.
You are right about the movement, but also bear in mind that each time you stop pedaling the motor continues to power on for a split second giving at least a quarter turn of the chain ring.
I’d like to see a groove placed on the inner or outer shaft to locate a O-ring or better still a primary seal, and perhaps Brose could address this.
Your layman’s solution could just work ok, but I would be inclined to pack the void with waterproof grease before inserting the O-ring. Derbies would be repelled by the O-ring and moisture would be repealed by the grease. I think this would be better as moisture would enter as the O-rings wore.
It’s too late for me, as my bearings when back pedaling are noisey af.
 

Bobtech

New Member
Dec 13, 2018
5
3
Norway
We are all on the same boat. Of course this is an issue that Specialized and Brose should work out. I did pack the gap with SKF bearing grease before mounting the oring. But as I am sure you can understand I can not open the motor to do any modifications as this will void warranty. If I had a free motor I would make it subsea proof.
 

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