Replacement Bearings for Bosch Ebike Motors Now Available!!

Haibike Rider

Haibike Rider

Member
Hi All,

Following the failure of my left-hand main crank shaft bearing in my Bosch Performance Line motor (identical bearing in the CX and earlier Active line) I tried to hunt one down. For three weeks I tried contacting every bearing supplier I could find, eventually tracking down the actual bearing manufacturer for Bosch who would not sell no matter what quantity I offered to buy!

Knowing a lot of people would soon be in my predicament with no alternative available I opted to have 1000 bearings manufactured. They are a like for like quality and have the same 2RS seal rating as the original bearing and they also carry the same Bosch 6004 LUV bearing designation.

I have photographed my own bike while fitting this bearing and constructed a how to guide for interest. I have also set up a website selling these crank bearings along with main motor bearings and overhaul kits etc. For people like me finding themselves out of warranty and little alternative than to buy a new motor!

There is a more detailed story on my site and I will add video and more techie info as I go. If you have any questions after reading the blurb on the home page I will be happy to try and answer them for you.

https://www.performancelinebearings.com
 
Wow, great guide. Thanks for posting.

But why do you need a "Bosch specific" bearing?
Any 6004 bearing will fit, they are the same dimensions. And the 2RS seal is okay but apparently not good enough for tough use, you can upgrade the sealing if you change the bearing to a LLU type. So get a 6004 LLU bearing and it will probably last longer.
 
Thank you.
I thought exactly the same thing about 6004 bearings. Like many others, I bought one and it didn't fit! Although the Bosch bearing has the 6004 designation, it has a completely different sized inner diameter and will not fit the crankshaft. As for the seal type, I too had the same thought and looked at a number of sealing options, including complex labyrinth sealed bearings, but these all come at the cost of added friction. If I had opted for one of these sealing systems and people found their battery consumption got worse after fitting my bearings, I think they wouldn't be happy! I have shown in the how too guide, how to get maximum life out of your bearings with minimum friction and there is a whole page of blurb on my home page that explains more or less what I have just written.
I think this will be an ongoing process and as I test and find improvements I will add them to my site, I have already done another page on the Haibike SES sprocket and how to get more life out of it. This will be added to the "How too" section today so please bear with me, this is a work in progress ;)
I hope this answers your questions?
 
As far as I could research online the left Bosch bearing has a 21.2-21.4 mm inner diameter depending on the source. This is only 0.6-0.7 mm difference in the inner race thickness from a standard 6004 bearing. I wonder if it would be possible to machine off the difference without losing structural integrity? There are, for example, cylinder honing tools from 20 mm cylinder diameter and up.
31-130145-large_1.jpg
 
Would it not be an option to get adapter rings machined, so it would be possible to use standard size bearings in the future?
There is for example the 61905 that is 25 inner diameter, 42 outer and 9 thick. Slightly lower static load rating, about 10%.
It would then need a ring machined that fits between the crankshaft and the new bearing (21.3->25 mm) and a small 3mm distance ring to keep the circlip happy.
 
Hi Tompat,
There is a lot of misinformation out there. If you look at the photo the left-hand bearing is a standard 6004 bearing, as can be found anywhere. On the right is the Bosch version of a 6004 bearing. Note the difference in thickness of the inner race. If you fancy honing that out to save a couple of quid, fill your boots :)
It cost me several months off the road and a substantial amount of money to have these bearings manufactured by a reputable bearing company to the exact size and specification of the original bearing.
It shouldn't matter what size it is? The main thing is, it's now available! And a lot cheaper than the only current alternative a £600 motor.
IMG_0375.JPG
 
tompat said:
Would it not be an option to get adapter rings machined, so it would be possible to use standard size bearings in the future?
There is for example the 61905 that is 25 inner diameter, 42 outer and 9 thick. Slightly lower static load rating, about 10%.
It would then need a ring machined that fits between the crankshaft and the new bearing (21.3->25 mm) and a small 3mm distance ring to keep the circlip happy.
Click to expand...

Why? you can now buy the bearing. And it's probably cheaper than a machined sleeve etc. Oh, by the way, it's not 9mm thick either.
 
Your efforts are truly appreciated. When I'll come to the point of left bearing replacement I'll surely check out your shop again.

The reason I want to explore options based on standard bearings is that when your 1000 bearings run out we'll all be in the same situation again. With an adapter or honing solution it would be possible to repair these motors beyond those 1000 bearings.
 
Haibike Rider said:
MudStop bearing protector
Click to expand...

I have a Performance Line Speed mfgt/bought in spring 2018. Is there any advantage in fitting a Mudstop protector ring to these? I've understood Bosch already has some sort of protection on newer motors and the Mudstop is mainly for older motors without this.

And way cool you have entire drive units for sale!
 
tompat said:
I have a Performance Line Speed mfgt/bought in spring 2018. Is there any advantage in fitting a Mudstop protector ring to these? I've understood Bosch already has some sort of protection on newer motors and the Mudstop is mainly for older motors without this.

And way cool you have entire drive units for sale!
Click to expand...
Hi Tompat, I believe the MudStop does work a lot better than the Bosch "seal". When I remove the gears to change the main motor bearing, you can see where the dirt and grit has come through the outer ring of the Bosch seal. I believe that because it is set within the motor cover, dirt sticks to the grease and then, because the seal is spinning and the cover isn't, over time the dirt winds its way between the seal and the cover and into the bearing.
This doesn't happen with the MudStop because it is formed around the outside of the cover, so much harder for the dirt to actually reach the grease in the first place.
Plus, I wouldn't be selling them if I thought they were no good! :cool:
 
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