Bosch chain came off.....

[Gubbins]

Today my chain jumped ship but luckily was near home so walked back to mess with it in the garage rather than in a feild. As it happens this was the right thing to do as it could not be coaxed back on the sprocket without removing the spider and chainring! Not good if miles away from home and no international rescue backup. This is the second time and in exactly the same place (coming slowly over a few stones off road downhill) so I need to understand what's afoot. Chain got past chain guard and guard mounting screws and was well stuck between chainring and engine casing. Any ideas on what's wrong and how to avoid this happening again would be greatly appreciated..
Thanks
Phill

 

[wissy]

This is exactly what had been happening to mine... (KTM Macina Dual HS) Initially I assumed it was the actual spider which was loose but it happened several times. The last time it happened was the same time the motor seized. Now I am unsure if they were related or just pot luck it happened that last time. It seems my hub is also an issue but I am unsure if this would have been a cause for chain to come off. Check spider is tight first?

Damned annoying the chain getting stuck.. always happened to me late at night as well ........ Shouldn't really get stuck there should it? really difficult to get chain off without taking everything off.

maybe David from electrifyingcycles can give you a clue based on what he's seen on my KTM which he is in process of fixing. Martin at ebikeshop may be able to suggest something as well. i never really did get issue solved.

 

[Martin@e-bikeshop]

Is it the Classic+ line?

 

[Gubbins]

Yes I think so. It's a 2013 model with the motor underneath.

 

[Martin@e-bikeshop]

My friend across the continent sells these Helps stop it coming off.

If you PM me I will forward you his details.

Regards
Martin

 

[EddiePJ]

If you are riding on rough terrain, I'd also think about a clutch rear derailleur.
It eliminated this issue completely from the BH, where as the Haibikes chain frequently jumps on rough terrain. I must add that this is absolutely no fault of Haibike or the system. Just my use of the bike. I might well get one fitted to that, just as an experiment.

 

[Gubbins]

Hi Martin,
Will do later.
It does have a chain guard on, which prevents refitting the chain in the normal way..

 

[Martin@e-bikeshop]

If you are riding on rough terrain, I'd also think about a clutch rear derailleur.
It eliminated this issue completely from the BH, where as the Haibikes chain frequently jumps on rough terrain. I must add that this is absolutely no fault of Haibike or the system. Just my use of the bike. I might well get one fitted to that, just as an experiment.

The clutch mechs do help significantly! Such a great invention into the MTB world.

Regards
Martin

 

[Gubbins]

Didn't know there was such a thing.. Googly Googly tonight I think

 

[Martin@e-bikeshop]

Hi Martin,
Will do later.
It does have a chain guard on, which prevents refitting the chain in the normal way.. View attachment 9106

Thats pretty much the same sort of thing. Try Eddies suggestion on a clutch mech. This should help a lot!

In stock now http://www.e-bikeshop.co.uk/eBike-Spare-Parts/shimano-xt-rear-derailleur


Martin

 

[Martin@e-bikeshop]

Didn't know there was such a thing.. Googly Googly tonight I think

If you want to know how it works then I have done a full write up on my blog.
You can find it here.

All the best!
Martin

 

[EddiePJ]

Martin@e-bikeshop, post: 227987, member: 5601[/EMAIL]]

In stock now http://www.e-bikeshop.co.uk/eBike-Spare-Parts/shimano-xt-rear-derailleur


Martin

Lovely.

Almost a shame to get it dirty.

 

[wissy]

Is that on the new haibike trekking?

 

[Martin@e-bikeshop]

Hi Wissy,

No the new Trekking has the Sram Dual Drive.
It is also running the new Bosch Performance drive which is near impossible for the chain to come off anyway.

Martin

 

[RobF]

The chain unshipped on the MH7 while going over a very modest bump.

Fortunately, no harm done, it didn't jam and I was able to put it back on at the roadside.

I suppose that is one advantage of the new Bosch motor, the small chainring makes it very unlikely the chain will come off.

Although I see some full sus mountain bikes come with a jockey wheel, like this AVE:

http://www.emotion-technologies.de/ebikes/ave/xh-offroad-pedelecs/

 

[halfer]

I've had this problem with my Ave XH-3, running the Bosch Classic crank drive. Good to hear it can be fixed!

Thanks Martin for that blog post. I have that on/off widget on my new KTM Action Macina, and I wondered what it was for.