Bosch failures?

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,815
Brittany, France
@High Rock Ruti , are you sure you weren't auditioning for a new Outdoor Summer version of Starlight Express ?????

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highrock.jpg
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,815
Brittany, France
BLITHERING IDIOT .. I thought I'd try my own thread intro title, but more me focused.

Isn't this the how to dress like "Mad Max - ebike warriors" , but still look good for the ladies thread ?
 

Beekeeper

🍯Honey Monster🍯
Aug 6, 2019
1,751
2,197
Surrey hills
This is a common story too. I do a lot of motors from hot dry countries and at the end of the day there are no seals other than the basic ones on the bearings, so dust or water, they will fail! MudStop and seal would help here (y)

Hi Bearing Man,

I’ve seen that the Bosch seal kit now comes with 5 felt rings which I have not seen before. Presumably they go into the non drive side crank just behind the circlip?


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Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
975
2,331
UK
Hi Bearing Man,

I’ve seen that the Bosch seal kit now comes with 5 felt rings which I have not seen before. Presumably they go into the non drive side crank just behind the circlip?
Very odd this one! As the younger members may not remember, up until the 1950's, felt seals were used before rubber seals were available. A felt seal was originally soaked in tallow (animal fat) before fitting, this was later replaced by soaking in oil. The felt seal was then normally capped by metal covers to try and keep any dirt and grit out.
These felt seals had to be kept wet with oil and clean. I think that the felt seals that Bosch have added, as you say, just behind the circlip on the drive side, would be ok on a road bike, if well maintained (hense 5 per pack!).
On a mountain bike, these seals soon get ingrained with grit and turn into a scouring pad! Not a great idea to smear them with sticky grease either? There was a good reason people stopped using felt seals back in the 50's!
Bosch could buy the double lip rotary shaft seal that we had manufactured to fit in this space. Our seal is low friction, lasts for the life of the motor, 100% water tight and totally unaffected by dirt, dust or grit. :unsure:
 

nasamorpheus

Member
Jul 17, 2020
186
95
Ljubljana
I keep reading threads from Specialized owners saying how they’re on their 2nd, 3rd, 4th... motor under warranty.
It seems the forum has a much higher Specialized ownership than anything else, so it would make sense that there are more posts about them.

The Gen4 Bosch is still fairly new, but how did the previous gen motors last? Did owners need 2 or 3 of these motors during their warranty period - or are they generally a bit more robust.

I’m going to place an order for a Trek Rail today, so am wondering about Bosch reliability. I usually get a new bike around every 3 years, so wondered if this will last... without any significant expense.
No issues, my girl has a Bosch active plus 3 gen, no problems, 2k miles, singing like new.
 

nasamorpheus

Member
Jul 17, 2020
186
95
Ljubljana
It's intresting how some people are getting more miles out there motors than others for me my first motor lasted 100 miles my second around 450 just having my third motor fitted. I am keen on my maintenance and regularly clean and 're grease the seal with Bosch grease I suspect it something to with the way I use the bike it's out in all conditions most rides are 25-30 miles and I like to pedal so I put a fare bit of force though the cranks I suspect this may not be helping
Man I don't know what motor you have but I just did 1000km with gen4 cx in three weeks in 25-35 Celsius every single day in hilly Alpine country Slovenia , couple of storms and motor is running like new. I don't know what are you sealing and maintaining but for sure it's not good for the motor I guess ;)
 

Old Mike

Member
Sep 3, 2019
58
48
Consett, County Durham
I went through three motors in 2 years. The first one only lasted 300 miles, the second and third did 900+ each. I ride in all conditions and never powerwash the bike but IMO it's the stupid small chainring at fault; crud collects round it and is ground into a paste by the chain and the forced through the bearings.

This makes a huge difference; there are 10,000KM motors out there in commuter-land.

That hasn't stopped me upgrading to a new Rail with the Gen 4 motor though.
Im up to 9,000 miles, 15,000 km-ish on my commuter bosch, still sweet as a nut.

Never gets washed, spray lube on the chain once a week. Onto my 4th chain, sprocket and cassette as they start to jump after a while, same gear constantly.
 
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kooly

Member
Apr 29, 2020
22
7
Australia
Had the Gen 2 CX (2019) for about a year and a half 1400kms and zero problems so far,,,had some chain suck in the mud..which was annoying..but no excess noise or motor issues...bit pissed off that the shop sold it to me as a gen 4 without me knowing which means i cannot get the 75-85Nm upgrade...
 

range

New Member
Jan 16, 2021
1
0
Glasgow
I've got a Focus Sam2 with a Gen 4 that has around 400ish miles on it so far ( bought early Feb 2021 ) and I've been feeling like it's just not been running properly for a few weeks now but have not been 100% sure as it's happened so slowly over that period. It definitely feels like it's a bit whinier, slightly gritty and a bit less efficient overall.

The other day the motor sounded like it spun really quickly without being engaged when I put my foot back on the pedal after dabbing through a section.

I've ridden in all sorts from super muddy to super dry dust. Have done 1 quick river crossing where the motor may have been slightly submerged. Usually wash the bike after most rides with a hose on shower setting.

Think it's time to contact the dealer I bought the bike from or am I overthinking it? It definitely still rides well enough for now.
 

maker

Member
Feb 13, 2020
63
32
North Wales
I've got a Focus Sam2 with a Gen 4 that has around 400ish miles on it so far ( bought early Feb 2021 ) and I've been feeling like it's just not been running properly for a few weeks now but have not been 100% sure as it's happened so slowly over that period. It definitely feels like it's a bit whinier, slightly gritty and a bit less efficient overall.

The other day the motor sounded like it spun really quickly without being engaged when I put my foot back on the pedal after dabbing through a section.

I've ridden in all sorts from super muddy to super dry dust. Have done 1 quick river crossing where the motor may have been slightly submerged. Usually wash the bike after most rides with a hose on shower setting.

Think it's time to contact the dealer I bought the bike from or am I overthinking it? It definitely still rides well enough for now.
I am 3rd Gen 2. Each replacement needed a clear problem before Bosch replaced. Intermittent grinding sound was not enough, it has to cut out.
 

Mteam

E*POWAH Elite
Aug 3, 2020
1,870
1,807
gone
I'm on my second bosch gen4 cx motor now, the first was replaced under warranty at around 500 miles after constantly throwing error 550.
 

Doug Stampfer

Well-known member
Jul 7, 2018
737
756
NZ
I've got a Focus Sam2 with a Gen 4 that has around 400ish miles on it so far ( bought early Feb 2021 ) and I've been feeling like it's just not been running properly for a few weeks now but have not been 100% sure as it's happened so slowly over that period. It definitely feels like it's a bit whinier, slightly gritty and a bit less efficient overall.

The other day the motor sounded like it spun really quickly without being engaged when I put my foot back on the pedal after dabbing through a section.

I've ridden in all sorts from super muddy to super dry dust. Have done 1 quick river crossing where the motor may have been slightly submerged. Usually wash the bike after most rides with a hose on shower setting.

Think it's time to contact the dealer I bought the bike from or am I overthinking it? It definitely still rides well enough for now.
You do know that the bosch has a "boost" feature? All it is is that the motor will overrun for a second or two after you stop pedalling. It is to get over tree roots & rocks etc without pedal strike. This can also happen if you put pressure on the pedal while stationary - it may want to take off on you.
I'd be interested to hear if you have a problem with it as I think I may have a problem with mine which I think is weird since I very rarely wash it, don't ride in the rain & have only once ridden quickly through a stream...
 

FJH

New Member
Jul 11, 2021
2
0
Houten
First Gen 2 lasted 6 months, replaced under warranty. Software needed reseting a few months later. Replacement motor making whining noise that last time developed into a grinding before siezing. So that will be 2 motors in 14 months. Apparently they don't like water which makes them unsuitable for where I live. Someone noted fitter riders have the problem as they exert more power through the pedals and the inadequate bearing and seal lets water in.
As an update in May I've had my third gen 2 in a 12 months of riding for a couple of Months and done a lot of exercise riding in the covid lockdwn. By now my previous two motors were making friction/grinding noises. The weather has been unuaually dry and I clean gently with water; motor gets more pressure thown up by tyres in the wet. So guess it'll be fourth motor this winter.

I have had a brand new Trek Rail 9 for two months and recently a high-pitched tone developed in the bosch gen4 motor. It fits the description of Maker. The sound only arises after cycling for a while in combination with slightly above average pedalling power of the rider. From 150Watt and up, slowly but surely, more and more noise comes from the motor during the ride.It is a noise similar to that of a disc brake, and increases as you exert more power on the pedals.

I have also ridden a ride without engine support, providing between 235 and 500 Watts input to the pedals. Then the noise arises much quicker and is also louder.

Oh, and I haven't ridden in the rain at all. I have only had one ride with a few very small puddles and then the bike had its first service. I can therefore not imagine that it has anything to do with moisture. I did hit the ground with my pedals a few times. But I hope that the bike is designed to cope with that.

Does anyone know more about this problem?
 

FJH

New Member
Jul 11, 2021
2
0
Houten
I have had a brand new Trek Rail 9 for two months and recently a high-pitched tone developed in the bosch gen4 motor. It fits the description of Maker. The sound only arises after cycling for a while in combination with slightly above average pedalling power of the rider. From 150Watt and up, slowly but surely, more and more noise comes from the motor during the ride.It is a noise similar to that of a disc brake, and increases as you exert more power on the pedals.

I have also ridden a ride without engine support, providing between 235 and 500 Watts input to the pedals. Then the noise arises much quicker and is also louder.

Oh, and I haven't ridden in the rain at all. I have only had one ride with a few very small puddles and then the bike had its first service. I can therefore not imagine that it has anything to do with moisture. I did hit the ground with my pedals a few times. But I hope that the bike is designed to cope with that.

Does anyone know more about this problem?
I took my bike to the store. There they took the time to carefully check the brakes again. It turned out to be a very precise job to which the mechanic devoted a lot of time and attention. The front disc brake was straightened in many places. And in this case straightening is only a matter of millimeters / micrometers. Sometimes in the center of the disc and sometimes in the far edge of the disc.

I was very surprised at the accuracy of the job and wondered how it is possible that these small differences could play a role while you are banging over all sorts of things with a bike like this. According to the mechanic, the tolerances on ever-increasing brake discs and calipers are getting smaller. He said that when putting pressure on the pedals it is possible that the discs will rub just a little bit. He turned out to be right. I have now done some test driving and the noise is completely gone. I still find it strange that the brake in the front wheel made noise when I put a lot of pressure on the pedals.
 

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