Bosch Long-Term Reviews And Recommendations

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
My Semi-Dysfunctional Love Affair with Bosch Powered E-Mountain Bikes
And Some Recommendations For Those That Get Equally Smitten


A Brief History


As with anyone who has experienced an e-bike for the first time, back in early 2016 my test ride at my LBS of a Bosch powered Cube Reaction 29er hardtail yielded instant ear-to-ear grins! It was love at first ride and shortly thereafter I stretched my budget to part with a small fortune and buy the bike.

Much joy on the trails ensued, punctuated by issues that saw my steed spending inordinate amounts of time back at the shop while the technicians and Bosch reps scratched their heads trying to figure out how to get the bike functioning properly again. I’ll outline all the issues and takeaways below.

In 2018, while picking up my now-not-so-beloved e-bike from the shop, after having its 3rd motor installed, I spotted what to me was the coolest looking bike I had seen to date – a Cube Nutrail Hybrid fat bike. I knew a test ride would be potentially dangerous, and it was…

My justification for the purchase was that this bike was an absolute beast with a big lump of a Bosch Performance CX motor (a step up from the current bike). The Nutrail looked as if it could survive the apocalypse! Surly this robust bike and motor system would be indestructible. Right?....

The decision to upgrade my bike was helped by the fact that both Cube and my LBS stepped up and offered a great deal on the Nutrail, after I reminded them of all the issues I had with the first e-bike I bought from them.

The Skinny On The Fat Story

Yes I was smitten again with the shiny new Bosch fat bike, but the tales of woe repeated themselves with this second love, to the point that I have considered, long and hard about going back to a standard meat-powered mountain bike.

Not-so-fun fact: The above idea was killed recently at the beginning of a three-hour ride in the hills outside Toronto, when the Nutrail popped an error code and the Bosch assistance ceased. Riding that long, or should I say riding and pushing a bike up hills, is not my idea of fun. :)

True Love

I’m currently reading Alain de Botton’s, “The Course of Love”, or at least the italicized philosophy bits – to cut to the chase in the reading. In the book he explains that we often put too much emphasis on the falling in love bit, as I have above. Turns out, true love happens over the long run, while enjoying the good times and hanging in there when the shitty stuff happens, which by the way is inevitable.

No doubt, I have been tested and I’m still hanging in there with my Nutrail. Having experienced years of e-mountain bike joy alongside the pain of ownership I feel equipped to offer some suggestions to those thinking about starting a relationship with an e-mountain bike.

I’ll start by stating the problems I’ve had with both bikes, for those that are interested:

2015 Cube Reaction Hybrid HPA Pro 29

This first e-mountain bike was fairly trouble-free to begin with, but developed ever-decreasing battery range estimates when riding on the same trails regularly. The bike made multiple visits to the shop and in the end the motor, battery, control unit, display and the wiring harness were all replaced – all under warranty.

Joyous rides resumed until the new motor started creaking when leaning into the pedals. The first trip to the shop after all of the above saw the motor mount bolts being retorqued. The subsequent trip to address the returning creak saw the dampening films between the motor and motor mounts being replaced. Another trip saw the motor mounts being retorqued again. The fourth trip saw the motor being replaced again as it was discovered that the bolts holding the two halves of the motor together were not properly torqued and the motor halves were rubbing together when cranking on the pedals thus creating the creaking. Retorquing these internal motor bolts was said to not be possible by the shop, thus the third motor.

As mentioned it was at this point that I bought the Nutrail Hybrid so I decided to shift this bike to a more distance biking role on gentler trails, to give it an easier life.

In the end I sold this original 29er to a friend who was aware of the history but took a chance on it when I offered it to him at a very attractive price. For me the electric fat bike did it all and I felt the second bike was redundant.

2018 Cube Nutrail Hybrid

As with the other bike, things started off rosey but it didn’t take long for the first issue to rear its ugly head. I’m happily riding the trails and my cranks start to disengage from driving the bike forward. As turns out a Cube engineer had not properly spec’d out the mating of the pair of cogs that connect the crank to the motor and drive line, and things just spun into a big mess.

As the cogs on the motor were all ground up in the process, the motor had to be replaced. So on to motor number two…

Number two was pretty good for a while and then it started making some clicking sounds, along with the dreaded motor creaking when really standing on the pedals. Internal gearing problems were identified and we were on to motor number three…

The third motor could be potentially the charm but the usual motor creaking has showed up again. This time I decided to take matters into my own hands and bought the tools to access to motor mount bolts and retorque them myself.

As expected, this worked for a while and the creaking returned. So now onto the dampening films…

Takeaways

When you are spending a pile of cash on a product that is supposed to be reputable, one does not expect the kind of issues that I have had. It seems to me, based on all the issues I’ve had and the reading I’ve done about e-bike systems, as of 2020 we’re all beta-testers – still at this point.

Sad really.

That said, I don’t want to be completely negative here – my bikes have been an absolute joy when they are working properly and not disturbing what, to me – on a good day, is an amazing meditation.

Recommendations

1. Know that when you buy an e-mountain bike, you are going to increase your maintenance regime beyond that of a normal bike.

2. Compare warranties from the various bike companies. You’ll need them. One good thing about the Bosch warranty is that if you replace a component, you get a fresh two-year warranty on the replacement part. This has been especially important to me, as you can tell above.

3. If you are new to e-bikes I would seriously consider buying your first e-bike from a reputable bike shop that is as close to you as possible. Confirm that the shop has a fully trained electric system tech so they’re not shipping your bike to another location, thus wasting more of your precious riding time.

4. Check to see if the shop stocks e-bike parts, like the motors, batteries, controllers, speed sensors, etc. This is rare, at least where I am located, and at best it takes a few days to get the required parts shipped to the shop. One time, I had to wait for few months for the next shipment of Bosch motors to arrive in Canada. Thankfully I was able to ride my clicking, creaking bike until the new motor arrived.

5. With the Bosch bikes and likely other brands, do retorque your motor mount bolts after the first good ride. This is made easier on certain new models where the manufacturers have smartened up and given access to the motor mount bolts without having to buy a bunch of special tools to access them. If I buy another bike, I’ll be looking for this feature.

6. if you’re not handy, when you are buying your bike, ask if the shop will include the retorquing of your motor mount bolts and a general check over of the bike after the first good ride – with the purchase price of the bike. Or better yet, get the shop to give you a deal on the tools and learn to access the bolts yourself. You’ll need these tools and the knowledge in the long run.


7. Most importantly, know that things will go wrong no matter how much your salesperson tells you how trouble-free these e-bike systems are. If you think otherwise, prepare to have your heart broken, again and again. :)

Rider Specs

I’m 6’ 1” and weigh 204lbs. I’ve always cycled a bit but really got into it after buying my first e-mountain bike. Prior to that my two-wheeled drug of choice (for almost forty years) were motorcycles, both on and off road. My e-mountain bike has now replaced my motorcycles. I ride the Nutrail as it was intended, on some wonderful trails in and around the Greater Toronto area.

Enjoy the meditation,

CubeHead


* See three year update further along in this thread.



Cube_29er_web.jpg


4B3A0087_web.jpg
 
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Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
969
2,319
UK
Normally I would say forget the factory torque settings and just go with F%8king tight, but Cube put the bolts in the wrong way round and use a nut holder and the motor to stop the nuts turning while you tighten the bolts. Any tighter than factory spec and the nuts round off the lugs on the motor and that's it, game over!
The damping film is a bit of a curse too. As you have already found out, it has a lifespan of about 3 months! I have seen other materials used here and some work well. It maybe worth making your own damper film from a harder material. It doesn't damp anything, it just stops the frame and motor rubbing together for a couple of months.
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
Normally I would say forget the factory torque settings and just go with F%8king tight, but Cube put the bolts in the wrong way round and use a nut holder and the motor to stop the nuts turning while you tighten the bolts. Any tighter than factory spec and the nuts round off the lugs on the motor and that's it, game over!
The damping film is a bit of a curse too. As you have already found out, it has a lifespan of about 3 months! I have seen other materials used here and some work well. It maybe worth making your own damper film from a harder material. It doesn't damp anything, it just stops the frame and motor rubbing together for a couple of months.

Thanks for the feedback Bearing Man and I'm glad I kept the torque to the factory specs. :)

Any suggestions for the best material for damper films?

I'm also curious whether there are any e-bike systems that are more trouble-free than the Bosch? I'm asking as, with a name like Bearing Man, perhaps you have some more experience with these systems than I.

Cheers, CubeHead
 
Jul 7, 2020
55
9
Wales
Interesting read and experiences.

How many miles are/were/have you done between fault intervals? Also I presume your riding is not particularly harsh, although being rigid I guess the motor is more susceptible to damage anyway?
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
969
2,319
UK
The best thing I saw was some thin, but quite hard plastic sheet. Unfortunately I never asked what it was?
Keep the water out of the Bosch motor and it is the most reliable by far. Fit a MudStop and seal to the right side of the bike, currently not much you can do with the left side, but if you don't blast the left bearing with a hose or pressure washer and don't go through water up to your knees, it will last you pretty well.

I make my living repairing ebike motors so I've learnt a few things over the years :)
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
Thanks for the tips and glad to hear that the Bosch system is good in the long run, as long as you take care of it. Speaking of which, I regreased the crank seal (see attached pic) and put a fresh Bosch bearing protection ring on it when I took the motor covers off last time. I try to stay out of the wet stuff as much as possible and I'm careful about cleaning the bike, so I'm hoping that this will do the trick if I do it once a year or so. Thoughts?

Bosch_bearing_seal.jpg
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
969
2,319
UK
Not to appear too negative but the Bosch seal is only slightly better than nothing at all. The seal meets the side of the case and as the mud and grit builds up in that area behind the sprocket, it just ends up being wound between the seal and the case where it enters the main motor bearing.
Depending on riding and cleaning, the grease should be refreshed every 2 to 3 months at the most.
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
Not to appear too negative but the Bosch seal is only slightly better than nothing at all. The seal meets the side of the case and as the mud and grit builds up in that area behind the sprocket, it just ends up being wound between the seal and the case where it enters the main motor bearing.
Depending on riding and cleaning, the grease should be refreshed every 2 to 3 months at the most.

Thanks again for the input. One last question, with the MudStop how long can I extend my service intervals?

Cheers, Richard
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
Interesting read and experiences.

Yes, I wish I had an experience that was a bit less eventful. :)


How many miles are/were/have you done between fault intervals?

If you mean how many rides can I do without any issues, I'm lucky if I get three rides in without something new turning up. It's glorious for those three rides though.


Also I presume your riding is not particularly harsh, although being rigid I guess the motor is more susceptible to damage anyway?

I ride it off road on single track mostly. I don't send it off jumps or launch it off drop offs but I do ride it as a trail bike, as it was intended. As mentioned previously, the only components that have failed were the electric system related, so they seem to be the weak link here.

Based on some of the issues I've read about on this site I don't think I'm alone here.


What's your experience?
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
969
2,319
UK
Thanks again for the input. One last question, with the MudStop how long can I extend my service intervals?

Cheers, Richard
Because this depends on your riding/cleaning habits, riding terrain etc. we recommend to take a look after 3 months and if it's still clean and greased, re-clean and grease and leave it 6 months next time, and so on.
 
Jul 7, 2020
55
9
Wales
What's your experience?

So far, pretty good. I had some concerns over some of the noises the unit was making when I first got it as it made a slight clunk but I believe that is just the clutch mechanism inside engaging.

I have done about 300kms on it so far and it still feels good and solid, I'm mainly hill bashing and doing the odd drop or jump but nothing big. I think having the rear suspension must serve to prolong the life of the motor mounts etc.

Not to appear too negative but the Bosch seal is only slightly better than nothing at all. The seal meets the side of the case and as the mud and grit builds up in that area behind the sprocket, it just ends up being wound between the seal and the case where it enters the main motor bearing.
Depending on riding and cleaning, the grease should be refreshed every 2 to 3 months at the most.

Is working on the motor in this way achievable for the average user (i.e. don't need specialist tools?) and will it void the warranty? Very helpful to know what to expect thank you.
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
969
2,319
UK
Is working on the motor in this way achievable for the average user (i.e. don't need specialist tools?) and will it void the warranty? Very helpful to know what to expect thank you.

You would need to buy a crank puller and a lockring tool (both available on our site :sneaky: ) These parts will not affect any Bosch warranty.
 
Last edited:

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
So far, pretty good. I had some concerns over some of the noises the unit was making when I first got it as it made a slight clunk but I believe that is just the clutch mechanism inside engaging.

I have done about 300kms on it so far and it still feels good and solid, I'm mainly hill bashing and doing the odd drop or jump but nothing big. I think having the rear suspension must serve to prolong the life of the motor mounts etc.

That's great to hear! Is this the latest Bosch Performance CX motor you are running?

Regardless of which motor you have, I believe it will be a good time to retorque the motor mount bolts. If you are not comfortable doing this yourself, have your experienced local bike shop do this for you.

With regard to what Bearing Man said about the MudStop and the maintenance of the crank seal, doing this yourself will not void the warranty.

If you have the older Bosch Performance CX motor like I do, one small point about a very thin o-ring you will encounter when accessing the crank seal. Be very careful to ensure that it is seated properly and that a thin coating of lube is applied when reassembling. This may be easier on a regular bike, but on my fat bike it is a bit tricky. When I was servicing the crank seal recently I discovered that the o-ring was butchered when my LBS replaced the previous motor.

This video shows how to take things apart, but doesn't mention the lubing of the o-ring. BTW, the lubing of the o-ring is a recommendation I got directly from Bosch Canada.


It's a shame that Bosch don't do their own servicing videos.


Cheers, CubeHead
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
IN LOVE AGAIN...

It's been over three years with my 2018 Cube Nutrail Hybrid and it's time for a longer-term update as a recent discovery has re-established my faith in the Bosch system, a least for now. :) Not so much for my LBS.

If you've read my original tales of woe at the top of this thread, you'll see that I've had my fair share of problems with my Bosch powered bikes. Motor creak has been one of my ongoing issues that had not been solved on my Nutrail. As you may have noted the next step for me was to remove the motor and replace the motor mount damping films, torque the motor mount bolts, put everything back together and hope for the best. I wasn't holding out much hope for this based on previous experience, plus I was informed that I would void my latest motor warranty if I pulled the motor out myself.

This spring, I was so fed up with the creaking that I decided to take the plunge. I had heavily-researched the motor removal and I had acquired all the necessary tools along with the new motor mount films. Upon removing one of the motor covers I saw this motor mount bolt with the rather large washer that looked rather unGerman. I had seen it when I had retorqued the motor mount bolts previously and although it did not look right I didn't want to mess with it for fear of voiding the warranty. See pic below:


Bosch_motor_mount_problem_01.jpg



The real AHAHH! moment would arrive later when I was able to extract the motor from the frame. What the technician (the head tech, BTW – Bosch trained) at my LBS had done was to install a bolt that was too long into one of the motor mounts. It was literally digging into the frame on the opposite side of the bike! This is something that you cannot see unless you take the motor out of the frame. See pic below:


Bosch_motor_mount_problem_02.jpg


Gee, I wonder if that's going to cause a creak when you stand on the pedals?...

My initial shock, followed by anger was quickly replaced by joy. I knew sorting these bolts and washer would solve the creaking issue!

Carefully figuring out which bolt should go where and testing that they definitely were not digging into the frame again was done and I methodically put everything back together and went out for a test ride.

On the road, at this point in my journey with Bosch, there was nothing sweeter than the sound of silence.

TAKEAWAYS

1. I can now completely understand why EMTB riders in the UK drive across the country to Berkshire Cycles as it seems so rare to find a shop that actually knows what they are doing when it comes to the electric bikes and their proper care. If you find a shop that can solve your issues to your satisfaction, please treat those people like gold as they are as rare as that material.

2. Better yet, learn all you can about your bike and its motor and battery system and don't be afraid to tackle your issues yourself. At least in my case, this was the best way to go and I feel chuffed that I was finally able to solve such a longstanding issue.

I'll leave you with a pic from a one of my latest and sweetest rides I've had with my beloved bike. May my Nutrail continue to provide me with joy for many years to come!

Enjoy your ride, Cheers, CubeHead


Albion_Hills_spring_2021_02.jpg
 
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Davemtb

Member
Jul 12, 2020
27
14
Australia
CREAKING ISSUE: Cannondale Moterra with Performance line CX gen 4. At 4600km and 2nd trip to LBS, the motor was replaced. The creaking was very loud when putting force through the pedals. Tightening the main motor mounting bolts gave a temporary fix (first visit). Bosch didn't hesitate to swap out the motor. The motor was still ok, but something to do with the mounting plate/bracket attached to the motor. Lucky still under warranty. I do at least 6000km/year mostly commuting plus hardcore trials. Mechanic said another bike was in the shop with same issue. There are other Bosch creaking reports of on the forum. These motor warranties should be distance based, not time based. A weekend warrior might only do a few thousand km after 2 years then the motor fails, and then they are left with the repair cost. On the plus side, if my motor keeps failing within the 2 year warranty, my bike will always have a new motor !:p
 

CubeHead

Member
Jul 22, 2020
15
8
Toronto, Canada
I was hoping that they may have sorted the creaking with the Gen 4 applications. Sad to hear that's not the case. I agree though, Bosch is good at replacing parts under warranty. From my side, I'm hoping the third motor in my Cube Nutrail will be the charm as it will be off warranty shortly. Actually, I've likely voided the warranty by fixing the bike myself...
 

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