Known Issues & Problems with Bosch Products + Help, Solutions & Fixes

[TrevorB]

Drive side. Not actually check left side. Most bearing failures are drive side. Some members from Pedelec uk forum have replaced bearings themselves, seemed reasonable straight forward.

Bosch sell service kits for seals but shops don't seem to know about it or tell their customers. Regular servicing and regreasingof seals would save Bosch a lot warranty replacements and bad PR.
It would be shop's best interest to offer free 3monthly service on eMTB, gets customer in door with option sell more bits or extra services.

 

[Durukan Devrim]

Drive side. Not actually check left side. Most bearing failures are drive side. Some members from Pedelec uk forum have replaced bearings themselves, seemed reasonable straight forward.

Bosch sell service kits for seals but shops don't seem to know about it or tell their customers. Regular servicing and regreasingof seals would save Bosch a lot warranty replacements and bad PR.
It would be shop's best interest to offer free 3monthly service on eMTB, gets customer in door with option sell more bits or extra services.

https://www.e-bikeshop.co.uk/Bosch-eBike-Drive-Unit-Bearing

This shop sell the bearing but only to their customers. I'd like to have a spare just in case.

 

[Deleted member 4210]

The bearing failures on Bosch mid drives are more common than reported on forums like this. The challenge with the Bosch, is that they have designed the unit with a very small chain ring, coupled with internal nylon gears that increase the speed transmitted from the riders cadence to 2.5 times. There is much more stress and higher bearing loads with this design right at the crank on the drive side, than there would be with more standard and larger chain rings. They do this to allow the motor to spin at higher RPM's, where its easier for the motor to maintain a consistent torque level across the range of gear changes. I'm not knocking their design - it's just a different design path Bosch chose to go, but each design path has it's pro's and cons. We'll probably see more mid-motor designs come out on the market with larger chain rings and multiple chain rings, to allow various riders who wish to have a certain cadence and to take better advantage of evolving and improving technology. We are still in the very early technology stages in terms of mid drive designs on e-bikes, so one can expect a lot more to come.

 

[Haibike Rider]

I found my left bearing (also open to the elements) had failed. So, not impressed that I couldn't find one! And being out of warranty, it was looking like a new motor! I had them made. If anyone is stuck for this bearing I have done a site and how too guide. You can find it here https://www.performancelinebearings.com

 

[Haibike Rider]

https://www.e-bikeshop.co.uk/Bosch-eBike-Drive-Unit-Bearing

This shop sell the bearing but only to their customers. I'd like to have a spare just in case.

I currently supply the e-bike shop so everyone can have a bearing no matter who they bought their bike from by buying from me Hopefully they will stop selling the Enduro bearing as they run out of stock. The "MAX" designation is for a static bearing, not a max strength bearing.

 

[Haibike Rider]

The bearing failures on Bosch mid drives are more common than reported on forums like this. The challenge with the Bosch, is that they have designed the unit with a very small chain ring, coupled with internal nylon gears that increase the speed transmitted from the riders cadence to 2.5 times. There is much more stress and higher bearing loads with this design right at the crank on the drive side, than there would be with more standard and larger chain rings. They do this to allow the motor to spin at higher RPM's, where its easier for the motor to maintain a consistent torque level across the range of gear changes. I'm not knocking their design - it's just a different design path Bosch chose to go, but each design path has it's pro's and cons. We'll probably see more mid-motor designs come out on the market with larger chain rings and multiple chain rings, to allow various riders who wish to have a certain cadence and to take better advantage of evolving and improving technology. We are still in the very early technology stages in terms of mid drive designs on e-bikes, so one can expect a lot more to come.

Many people put main motor bearing failure down to high torque loads, but compared to other bearing applications, the main motor bearing in a Bosch motor gets a pretty easy life. If failure was due to high load issues, the bearing would be worn but not destroyed and full of rust! They should also all fail within a relatively close time or mileage count and they don't. I have now spoken to many people and there is a pattern.
If you jet wash your bike, you could expect as little as 500 miles from a bearing. If you dry commute 6 -7 thousand miles seems the norm?
So, agreed, there is an issue with Bosch motors, but it's not the bearings, it's the lack of water tight seals.

 

[GuruUno]

Does anyone have a serial number range of the affected units that may have the crank bearing issue to check against?

 

[Haibike Rider]

Does anyone have a serial number range of the affected units that may have the crank bearing issue to check against?

From what I can gather, it happened from the first motors and is still happening now. But it's still not a bearing issue! It is a seal issue. If you get water near these bearings, they WILL fail.
The seal mod offered by Bosch can only help if you replace the silicone grease on a very regular basis. Again, the Bosch seal mod is not a water tight seal. The bearings themselves are sealed but they are only there to stop the grease drying out and dust getting in. They won't stop water. As soon as rust develops inside the bearing its the beginning of the end!

 

[GuruUno]

That's good info. So then, how would one approach the service aspect of resolving the problem now that it is in its beginning stages?
A Trek warranty issue or?
In any event, what would be the resolve, disassembly, new bearing and seals or?
How often and what would need to be done to have it not happen again?
I know you say replace the silicone grease, but is that part of a service by Trek during the warranty period or my responsibility?
And who evers' responsibility it is, would you know if it is documented and described by Trek?

 

[Haibike Rider]

Good questions! If your bike is under warranty, the motor should be replaced by Bosch through your Bosch dealer. If you don't want the agro or the down time it takes for them to send your motor away for repair/replacement, then looking after your bearings is or changing them yourself is your only options.
However, if you change your own bearings whilst under warranty, you will void any further warranty! Should you have a more serious issue down the line, you maybe kicking yourself!
How often you re-grease your bearings would depend on how often/far you ride, whether it's wet or dry, how you clean your bike etc. As for who's responsibility? I would have thought Trek would re-grease the motor bearing but your service intervals will be too far apart to help much, so again it's up to you. As you're still under warranty you don't need to be overly concerned, but anyone out of warranty should keep an eye on it.
I have no idea what Trek's policy or documentation states on this issue?

 

[Haibike Rider]

Hi All,
Just to keep you up to date. I have now sourced, or had made, just about every bearing in the Bosch Active and Performance line and CX motor. I have also added a video on how to change these bearings. The link can be found on my "how to" page. https://www.performancelinebearings.com
Thanks for anyone following this and please share if you can.

 

[Haibike Rider]

Me again! I have just uploaded a new, more in-depth video showing a completely worn out CX motor being bought back to life! Every single bearing was bad!

again, please share to other forums if you feel it would be helpful.

This is a picture showing just one of the bearings from this motor. I also think I may have found the cause of this sort of water ingress. I will post a report once I am sure of my findings.

 

[DanRichman]

Forgive me if this has been asked and answered.

After a mere 800 miles, my Bosch Performance Speed engine suddenly developed a number of bizarre noises -- faint grinding, crackling sounds -- and there is more play in the pedals than before. There's a looseness detectable when I alternate slight backpedal and forward-pedal, and there's more forward travel of the pedal required before I'm propelled forward.

I am dreading a diagnosis, because I fear it's a problem with one or more bearings. There's no looseness in the crank bolts.

Thoughts? It's OK; I can take it.

 

[Haibike Rider]

Brace yourself Dan!...Only kidding It sounds like you just have a main motor bearing gone and maybe a dose of paranoia? You have listed several findings that can all be attributed to different things so it may not be as bad as you fear.

When you say there is more play "in the pedals" I am assuming you mean the pedal arms? and this play is coming from the motor? There is naturally some 'back-lash' in the gears but if you are physically feeling this whilst pedalling then this will also be caused by the play in the crankshaft (Caused by the main motor bearing failure)

The "more forward travel of the pedal" that you mention is not normally associated with bearings, unless your motor is truly wrecked! (Don't panic again! A truly wrecked motor normally sounds horrendous).

The motor must see 4.5kg of force through the pedal arms and also see that the back wheel is turning. So it can be that you have just stopped with the rear wheel in a position that it has to do a complete revolution before the magnet on your spokes passes the speed sensor, and especially if you are in higher gears, it can take what seems like a long time for the motor to kick in.

I would suggest having the motor changed if it's still under warranty? Or bearings checked out if it's not. (don't worry, I ship to the states )
Once your bike is fixed, apply the silicone grease and dust seal, but apply the grease to the inner crankshaft bearings both sides of the bike as well as the main motor bearing (as in pictures below). Don't jet wash your crank and don't wash or store your bike on its side and you should be good for the next 6000 miles

 

[Dmitri]

Just in case anyone here is getting Error 530, I've been getting it persistently for a few weeks, so the advice is to remove the batteries and replace them. So I removed both batteries and one of them had lots of dried dirt/dust right inside the contacts. Just blowing inside (or vacuming, I suspect) fixes the problem. But hey, you could be getting this for other reasons. I'm just leaving it out here in case anyone has the same issue.

 

[Dmitri]

Just in case anyone here is getting Error 530, I've been getting it persistently for a few weeks, so the advice is to remove the batteries and replace them. So I removed both batteries and one of them had lots of dried dirt/dust right inside the contacts. Just blowing inside (or vacuming, I suspect) fixes the problem. But hey, you could be getting this for other reasons. I'm just leaving it out here in case anyone has the same issue.

 

[bob armani]

Me again! I have just uploaded a new, more in-depth video showing a completely worn out CX motor being bought back to life! Every single bearing was bad!

again, please share to other forums if you feel it would be helpful.

This is a picture showing just one of the bearings from this motor. I also think I may have found the cause of this sort of water ingress. I will post a report once I am sure of my findings.

Haibike Rider- This is one of the best and most informative videos I have seen to date. Great to see how the internal parts work in these motors. A lot to absorb, however, after a half a dozen views, you could become a pro with the right tools of coarse. LOL! A wealth of information here. Probably good for another 100k miles after the rebuild. Thanks for sharing.

 

[Scooteretti]

@DanRichman Since you only have 800 miles on your bike I presume that you may have purchased the bike less than 2 years ago? If yes, don’t touch or take apart anything on your drive as you Bosch system is covered under warranty. Your Bosch authorized dealer will be able to assist you.

If you take anything apart before the warranty expires it will be voided. In North America Bosch is very responsive to getting replacement parts out within a couple of days. So their service is typically top notch and certainly one of the best of any brand here.

 

[mca59]

An issue that I have recently discovered is that over-tightening a crank arm bolt can lead to the crank pressing into the lock ring which is mounted on the motor's shaft. This pressing can lead to the lock ring breaking/snapping. See photos for reference.
View attachment 19047View attachment 19048View attachment 19049View attachment 19050View attachment 19051

Hello,
I was looking a lot for this lock ring but it seems it does not exist!
Theoretically it should be a DIN 471 UNI 7436 NA S type lock ring, and the item number should be 84. But while it can be easily to find the NA type (that is identical but just thinner, 0.042 inch or about 1 mm), the NA S type, that should be identical but with a 0.078 inch thickness (about 2 mm), seems to be impossible to find...
So, I would like to know if you were able to find this lock ring replacement and where.
Thanks a lot.

 

[Haibike Rider]

Hello,
I was looking a lot for this lock ring but it seems it does not exist!
Theoretically it should be a DIN 471 UNI 7436 NA S type lock ring, and the item number should be 84. But while it can be easily to find the NA type (that is identical but just thinner, 0.042 inch or about 1 mm), the NA S type, that should be identical but with a 0.078 inch thickness (about 2 mm), seems to be impossible to find...
So, I would like to know if you were able to find this lock ring replacement and where.
Thanks a lot.

How many would you like?
In fairness you are right, the actual circlip used by Bosch is like their bearings, a bespoke part! I have been searching for 6 months! And as no one would make them for me (unless I wanted 50,000 or more!) So, I have found the closest possible match. They are 0.078 (2mm) thick, then I have to give them a slight tweak and a touch on the grinder to make them identical to the original Bosch ones.
A pain to do but it's the only option available at this time.
Give me a shout through www.performancelinebearings.com and I will help you out.