Fairly obvious.
Its a guide to keep the chain on a single chainwheel so when shifting on the
rear derailleur the chain wouldn't pop off the top and derail.
All of you have seen the wave in the chain in fotos taken in action on roads
and this same action could unseat the chain on top when shifting.
The chain angle on many bikes could also cause the chain to climb when in
the out or inside cogs depending on shape of chainwheel tooth and chain
interfacing.
Crunch, crunch, "Oh S---!"!!
Many of you have beenther even with a conventional double/triple chainring
front derailleur cage.
Ted Ernst
Palos Verdes Estates
CA USA
> Does anyone know what the following Campagnolo item is:
> http://ebay.com/
> alternatively, Ebay number:380150117371.
>
> It appears to be a front derailleur or chain guide of some sort as the
> seller states. Is there a piece missing? Under what circumstances would
> this mechanism be used?
>
> Thank you.
>
> Cheers.
>
> Tom Hayes
> Chagrin Falls, Ohio USA