Can a Bosch Performance chain guard be purchased separately?

halfer

Esteemed Pedelecer
I'm still running a KTM Action Macina 29 (2014 model with Performance drive and Intuivia display) and have now done 4300+ miles. Aside from a couple of hiccups I've been extremely happy with it. It's probably around 18 months old now, so could probably do with a bit of TLC.

Last year I contacted KTM to see if they could source the chain guard (black ABS plastic, see image) as the lugs were not very reliable, but KTM was unable to. Thinking about it, it is probably a Bosch item rather than a KTM item anyway. So, for the last year I have used an unobtrusive bungy cord to keep the guard on, which it has done very well. However the plastic lugs have finally given up, and the chain is now struggling to stay on. I thus think I need to make a better effort to find a replacement part!



I have found a Bosch guard for "Gen 2" on eBay, but I don't know if this would fit - it does look different (see image). It's mail order from Australia as well, which is a bit of a way for the UK market.



Anyone know if these parts can be sourced from a UK seller, and if so who they would recommend? I've done a bit of searching, and have found crank arms and sprockets from specialists and eBay, but not chain guards. I am not fussed about matching the exact part, as long as it fits, does what it is meant to do, and is reasonably in keeping with the bike.
 
Last edited:

halfer

Esteemed Pedelecer
Thanks soundwave - I don't know. Does a "bash ring" keep the chain on? The thing I have at the moment is enclosed, so presumably works against chain bounce as it tries to jump off the sprocket. I can't see how that would do the same - but happy to be wrong!

My current chain stay also snaps into the drive casing, and does not connect to the sprocket or axle.
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370

halfer

Esteemed Pedelecer
you sure your chain is not too lose?
I'm not certain, but it seems OK to me - there's no appreciable slack, and pressing down on the chain gives a satisfying amount of bounce. I'm on my second chain/cassette, but I seem to recall the first one had the same problem - if the guard was off, the chain would stay on for a couple of hundred yards. Is this not usually the case?

Bravo, thanks! Had I known to search for "Kettenschutz Horn A14ES schwarz" I would have found it :rolleyes:

I'll have a look at the one that covers more chain too, but I suspect I'll just go for the identical part, given that it is likely to Just Work!
 

halfer

Esteemed Pedelecer
Thanks for the extra images - a chain tensioner is a good idea.

Incidentally, my drive sprocket is around two inches in diameter, with probably 11 teeth - a consequence of having a Bosch central crank drive. There's not nearly as much for a chain to hang on to, compared to the full-size crank in your pics!
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370
you could try a bigger sprocket at the front i have 16t on my haibike, tho then not sure that guard will fit.?

what are you doing on the bike to make the chain come off?
 

halfer

Esteemed Pedelecer

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370
have you changed the front sprocket ? as that small it will wear out fast and even faster if the chain is flying off it and back on.
 

halfer

Esteemed Pedelecer
you can also have 2 sprockets on the front
What is the purpose of two sprockets? Is the idea one can change the sprocket in use easily, in order to change ride/speed characteristics?
 

halfer

Esteemed Pedelecer
have you changed the front sprocket ? as that small it will wear out fast
That's a very good point, thanks - I've thought about it, and haven't got around to it. I will put the bike on the stand at the weekend, and clean it all up, so I can see the sprocket's condition. After heavy mileage (see above) it probably is due for replacement!
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370
4300 miles and not changed it lol its done dead finished long ago.

you need the spanner to remove the lock ring dont try hack it off as plastic.
 

halfer

Esteemed Pedelecer
New 4300 miles and not changed it lol its done dead finished long ago.
Your comment encouraged me to get the bike onto the stand immediately, and whilst I rarely take a look under the cover to know what new looks like, I would be very willing to believe my battered cog needs replacing! I'll get this ordered first. Thanks!

To be fair, it would be nice to have a guard that doesn't come off, so I'll get a Kettenschutz Horn on the go too :D
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370
i have a 19t connex 1 from Germany you can have for 10 quid brand new tho doubt you like it with out a dongle.

 

halfer

Esteemed Pedelecer
i have a 19t connex 1 from Germany you can have for 10 quid brand new
Hmm, I might get that from you. I've just "counted me teeth" and it turns out I'm running a 16-tooth sprocket, and I wouldn't mind a bit more resistance/speed. A new, identical guard should fit over that - there's a good 25mm clear on all sides.

I expect I'll need a spider, then? Thirty quid, grumble :eek:
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,650
4,370

halfer

Esteemed Pedelecer
Eek, that's three things! I take it the spanner and the spider do the same thing? The spanner works on its own, whereas the spider needs a (torque) wrench plugged into it?

If I've understood the above correctly, what does the third thing do? o_O