Front sprocket detached from crankset - Why? Has it happened to anyone else?

[Andy-Mat]

Andy - many people on here, like me, may have had the very limited experience of one hub motor and one crank motor - in the Carrera bikes from Halfords. Admittedly the hub implementation on the Carrera Crossfire must have been faulty from a design or spec point of view as many many owners have had problems. Whereas the Bosch implementation of the mid-drive on the Carrera Crossfuse, seems almost trouble free.
Anyway back to the original post - I thought when I first read it that you must have a Carrera Crossfuse, because I discovered after a few hundred miles on mine that all the bolts that held the front sprocket were backing out. Halfords stripped it and applied loctite which must have been missed at the factory, and I understand that at least my local Halfords store routinely loctites them now on assembly.
Mike

Both my own bikes were basically generic Chinese made rear hub motors, of otherwise unknown make. Neither one has had any problems that needed any attention whatsoever.
I could not even say if they were Loctited or not, no idea! Total ownership time almost 10 years. They never ever failed or needed attention, just get on, accelerate and ride!
JUST HOW IT SHOULD BE FOR ANY E-BIKE!
If you could simply take the time and trouble to read carefully the various articles I posted on the subject, you would read of the differences between mid and hub motors, written by bike Jounalists, talking about the industry as a whole, and not about your bike or my bikes....
Never forget, that individually, there are always exceptions.
The mass of mid motor and the mass of hub motors (as in this case) need to be carefully and correctly understood....that is NEVER achieved with only 2 or 3 examples.
If you wish and if you can read German, I could look up the many unhappy German owners of Bosch bikes over many years, and the awful problems they have experienced!
Here is a page of problems, some even in English for you:-

probleme mit Bosch e-bikes - Google Search

Have a great day.
Andy

 

[Gringo]

Then consider yourself very lucky.
Nobody, especially not me, is saying that it happens to all owners of mid motor bikes, but they do stress the drive train/chain, more than any other e-bike system.
Its also patently obvious for anyone who has at some point, trained and worked as an engineer, but not so obvious to anyone NOT so trained.
Furthermore, the links I provided all maintained the same single point of concentrated stress, but you may have not read all that I posted, so you would not even know that!
Have a great day you lucky person you!
Andy

1/ yes I am lucky
2/ yes I understand drive components wear quicker on mid drive motors
3/ yes I am a engineer, time served, qualified toolmaker and machinist for experimental work
4/ no I haven’t read all you’ve posted, it’s not that I’m lazy, it that I don’t care
5/ yes I will have a good day thanks

 

[Andy-Mat]

1/ yes I am lucky
2/ yes I understand drive components wear quicker on mid drive motors
3/ yes I am a engineer, time served, qualified toolmaker and machinist for experimental work
4/ no I haven’t read all you’ve posted, it’s not that I’m lazy, it that I don’t care
5/ yes I will have a good day thanks

You said, and I quote you:-
4/ no I haven’t read all you’ve posted, it’s not that I’m lazy, it that I don’t care
This also means that you are basically uninformed, as thats how YOU want to be!
So your opinions, at best, are flavoured with a deep lack of knowledge!
Your own personal choice of course!
Thanks for the "eye opening" statement.
Andy

 

[georgehenry]

Hi Andy,

I have read and viewed the links you provided and thought they were good.

The NYCE wheels guy explanation was particularly good I thought.

He also mentioned test riding the bikes you think are right for you. This is for me an essential part of the buying process. When I bought my Oxygen I test road it against quite a few other bikes and just preferred it.

I almost wish I lived near his shop, though as an overweight 58 year old asthmatic coupled with the way the US Health system has coped with Covid19, particularly in New York, maybe not.

Just buying a bike online from the specifications and price is a recipe for disaster with perhaps Woosh bikes being an honorable exception and there may be a few others I am unaware of.

Also another important factor for anyone not that interested or capable of looking after their bike themselves should be to source their bike from a good dealer reasonably close to them where they can take it to be fixed if it goes wrong.

After re reading your first post it is mostly reasonable but the part that has probably raised a few hackles was at the end where you are really voicing your strong personal opinion.

"I cannot think of one single positive reason to buy such a bike....
I can only recommend, in the long term, a bike with either a rear (my favorite) or front hub, as they will get you home with the chain removed.
Mid motors won't...
Been there, done that and got the T-Shirt! (I mean that I have ridden home, up hill and down dale without a chain, on a rear hub motored e-bike.)
Mechanically, mid motor bikes are designed for countries like Holland, with basically no hills, far less chain drive stress...! "

Now everyone is entitled to their opinion but to say that mid motors are designed for the flat is really a contradiction of, for me the main strength of a mid motor in comparison to a hub motor where mid motors are better at climbing steep hills.

I got my Yamaha Haibike hard tail for its ability off road and to allow me commute to work using in places quite demanding technical single tracks with steep uphills and down, roots, rocks, sand, mud steps and where my dear old rear hub Oxygen bike would just not have coped or fallen apart in the attempt.



I did use the Oxygen on a route to work that included less demanding off road tracks and it coped surprisingly well but only up to a point.

I paid £1400 for the Oxygen and £1750 for the Haibike and although both are good the quality of the Haibike is better and even in its entry level guise has proved tough and durable and very capable in tough off road conditions. Certainly worth the £350 differential in price.

However for relaxed reliable commuting on the road in a not too hilly area a simple cadence sensor rear hub generic Chinese derived bike is all you need and will provide superb value coupled with a vastly de stressed drive system that will last an order of magnitude longer than a crank drive. And yes if you have a now illegal unrestricted throttle it will get you home if the chain breaks. If you are capable of doing so, you will be able to source cheap parts to repair it off the internet.

So if I only rode on the road and wanted a relaxed ride where the bike takes a lot of the strain off the rider I would get a rear hub drive bike. I use my Oxygen for all my errands and shopping trips, or used to before Covid19 struck.

One particular disadvantage of a rear hub motor bike not mentioned and is important to be aware of is issues with spokes breaking in the motor wheel that are quite common.

I had that with mine and did fix it myself but for some people changing spokes and truing wheels is beyond their comfort level. I have seen plenty of posts on hear from people with that problem, and it is not so easily fixed as normal bike shops cannot cope with a motor wheel.

I have never owned a Bosch powered bike, so cannot comment from personal owning experience.

I think anything you buy that has soft wear that makes it harder to fix works for the manufacturer not the individual. You pays your money and makes your choice.

I had to fix the battery and charger connections on my Yamaha charger and battery myself when they broke as the only option otherwise was to buy a new charger and battery.

 

[Gringo]

You said, and I quote you:-
4/ no I haven’t read all you’ve posted, it’s not that I’m lazy, it that I don’t care
This also means that you are basically uninformed, as thats how YOU want to be!
So your opinions, at best, are flavoured with a deep lack of knowledge!
Your own personal choice of course!
Thanks for the "eye opening" statement.
Andy

Just to clarify things, I am reasonably knowledgable with an above average amount of mechanical sympathy so it’s not the subject that I don’t care about, it’s you on your soapbox, you won’t be happy until everyone rides a hub motored bike and is capable and willing to do all of there own maintenance / repairs.
All That said, I wish you well and hope you are having as good a day as I am.
ive all ready had an analogue ride for exercise this morning, I’ve two drill sets to sharpen for my less mechanical minded friend and then im going up the woods on my BOSCH powered Cube just for a laugh.

 

[Andy-Mat]

Hi Andy,

I have read and viewed the links you provided and thought they were good.

The NYCE wheels guy explanation was particularly good I thought.

He also mentioned test riding the bikes you think are right for you. This is for me an essential part of the buying process. When I bought my Oxygen I test road it against quite a few other bikes and just preferred it.

I almost wish I lived near his shop, though as an overweight 58 year old asthmatic coupled with the way the US Health system has coped with Covid19, particularly in New York, maybe not.

Just buying a bike online from the specifications and price is a recipe for disaster with perhaps Woosh bikes being an honorable exception and there may be a few others I am unaware of.

Also another important factor for anyone not that interested or capable of looking after their bike themselves should be to source their bike from a good dealer reasonably close to them where they can take it to be fixed if it goes wrong.

After re reading your first post it is mostly reasonable but the part that has probably raised a few hackles was at the end where you are really voicing your strong personal opinion.

"I cannot think of one single positive reason to buy such a bike....
I can only recommend, in the long term, a bike with either a rear (my favorite) or front hub, as they will get you home with the chain removed.
Mid motors won't...
Been there, done that and got the T-Shirt! (I mean that I have ridden home, up hill and down dale without a chain, on a rear hub motored e-bike.)
Mechanically, mid motor bikes are designed for countries like Holland, with basically no hills, far less chain drive stress...! "

Now everyone is entitled to their opinion but to say that mid motors are designed for the flat is really a contradiction of, for me the main strength of a mid motor in comparison to a hub motor where mid motors are better at climbing steep hills.

I got my Yamaha Haibike hard tail for its ability off road and to allow me commute to work using in places quite demanding technical single tracks with steep uphills and down, roots, rocks, sand, mud steps and where my dear old rear hub Oxygen bike would just not have coped or fallen apart in the attempt.

View attachment 35352

I did use the Oxygen on a route to work that included less demanding off road tracks and it coped surprisingly well but only up to a point.

I paid £1400 for the Oxygen and £1750 for the Haibike and although both are good the quality of the Haibike is better and even in its entry level guise has proved tough and durable and very capable in tough off road conditions. Certainly worth the £350 differential in price.

However for relaxed reliable commuting on the road in a not too hilly area a simple cadence sensor rear hub generic Chinese derived bike is all you need and will provide superb value coupled with a vastly de stressed drive system that will last an order of magnitude longer than a crank drive. And yes if you have a now illegal unrestricted throttle it will get you home if the chain breaks. If you are capable of doing so, you will be able to source cheap parts to repair it off the internet.

So if I only rode on the road and wanted a relaxed ride where the bike takes a lot of the strain off the rider I would get a rear hub drive bike. I use my Oxygen for all my errands and shopping trips, or used to before Covid19 struck.

One particular disadvantage of a rear hub motor bike not mentioned and is important to be aware of is issues with spokes breaking in the motor wheel that are quite common.

I had that with mine and did fix it myself but for some people changing spokes and truing wheels is beyond their comfort level. I have seen plenty of posts on hear from people with that problem, and it is not so easily fixed as normal bike shops cannot cope with a motor wheel.

I have never owned a Bosch powered bike, so cannot comment from personal owning experience.

I think anything you buy that has soft wear that makes it harder to fix works for the manufacturer not the individual. You pays your money and makes your choice.

I had to fix the battery and charger connections on my Yamaha charger and battery myself when they broke as the only option otherwise was to buy a new charger and battery.

A good post, showing a far deeper understanding than some other recent ones on Pedelec! Particulrly when a bike is a system, that all the parts have to communicate with each other as Bosch apparently sells. That too puts me off such products completely.
Interesting that you mention spokes breaking, I have hear about it before, but never had one break on either bike up to now. The people that I have known with broken spokes, have had them happen again and again, sometimes with some months in between, on the same wheel, strange.
Obviously we cannot know if they were fully and correctly adjusted, and I have never had the need to touch mine, (why would I "repair" a running machine?), but I have looked forward to maybe one time needing to do it!
The single worst problem I find with rear hub motors are repairing punctures, so I always buy puncture proof tyres, and have usually added the tread off an old tyre between the tube and the inside of the tyre, which means that I have not had any punctures for some years, but I also replace the tube and the tread, each time a tyre is worn out. Reusing an inner tube is not a good idea I find!
If I ever had a spoke break, I would get the same size/thickness as I already have, so as to not change the local stresses in the wheel, and I may get a professional person to actually do the job.
But not yet decided 100%!
Again many thanks for your comments, they show a good understanding of e-bikes.
Andy