What’s this?

[Markymark]

Little rubber thing that sits just behind the chain ring. Never noticed it before until it came loose and started flicking against the chain ring. Tightened it back up but no idea what it’s for.

 

[rogerzilla]

Chain watcher to prevent chain drop?

 

[Salty seadog]

^^^^ I reckon the same , to stop the chain getting trapped between chainset and frame.

 

[Markymark]

It does look like it’ll hold something but doesn’t lock into place as such, I can twist it and tighten it with a degree of flexibility.

 

[JhnBssll]

Twist it until it only just clears the chain then tighten it up - as said above its to stop the chain coming off the inner ring and making an expensive mess of the carbon frame

 

[Spiderweb]

Google image search 'chain catcher' and you'll get the idea.

 

[Markymark]

Thanks all.

 

[Ajax Bay]

Chain watcher to prevent chain drop?

This won't "prevent" chain drop.

. . . to stop the chain getting trapped between chainset and frame.

This.

Twist it until it only just clears the chain then tighten it up - as said above its to stop the chain coming off the inner ring and making an expensive mess of the carbon frame

The aim in positioning is to set it up so that 'if' the chain drops off, it's caught. If you set it up so it "only just clears the chain" recognise that there's a danger that the dropped chain will ride over the chain catcher and possibly damage the frame.

 

[Spiderweb]

I had a small issue with the chain occasionally dropping off the smaller front chainring, this only happened when shifting from the big to the little ring whilst in the top two lowest gears on my cassette, no amount of tweaking the limit screw could sort this. The Tricross was already fitted with a Deda dog fan chain catcher which did its job and caught the chain but it didn't prevent the chain coming off. I moved the dog fang positioning it higher up level with the chain and closer to the chain (3mm ish) and have never had a chain drop off since.

Great bit of kit for not a lot of money.
https://www.chainreactioncycles.com/deda-elementi-dog-fang-chain-catcher-/rp-prod84217?gs=1&sku=sku325974&pgrid=60711843258&ptaid=pla-425589036369&utm_source=google&utm_term=&utm_campaign=PLA+All+Products&utm_medium=base&utm_content=mkwid|sJLWdFXGz_dt|pcrid|309840119912|pkw||pmt||prd|325974UK&gclid=EAIaIQobChMIiIzl0t303wIVKLftCh0A5wglEAQYCyABEgKI8fD_BwE

 

[JhnBssll]

I use the K-edge braze-on style chain catcher on the 3 road bikes, good bit of kit This one is intended to run slightly clear of the chain and prevents it derailing rather than catching it after the event; I didn't realise there was a difference, seems daft to try and catch a dropped chain when you can efficiently prevent it

 

[Slow But Determined]

Twist it until it only just clears the chain then tighten it up - as said above its to stop the chain coming off the inner ring and making an expensive mess of the carbon frame

Don't I know it!!!! I now have one fitted!!