Bicycle Mechanics - Front derailluer issue...

I have a Bianchi Giro with a 105 triple. The problem I have is with the middle ring. When shifting up from the small, or down from the large I get chain rub. It doesnt matter what cog I am in. To alleviate this I have to push the left shifter, it moves the derailluer, I hear an audible click and the chain rubs no more.

According to Zinns book this is not feathering as the book indicates you dont have that ability with a triple.

This a new issue that just started. Any thoughts on how to rectify this?

Thanks.

John

Really no clue, but I'm curious if your derailleur mount is moving?

Really no clue, but I'm curious if your derailleur mount is moving?


No, no movement of the mount.

Most Shimano road triples, including your 105 have four positions for the front derailleur. The two middle positions should be found on either side of the middle chain ring and should be used to trim the front derailleur. With the chain on the middle chainring You should be able to use all of the cogs on the cassette by choosing one or the other of the middle positions.
Depending on the vintage of your shifters you will probably have a soft click trim position available on the small shift lever when on the smallest chainring.
Instructions for adjusting derailleurs can be found at the Park Tool website.

Al

Chain rub in every cog? First if you have a work stand or indoor trainer put it in and see if it really is chain rub. When I think of chain rub I'm thinking chain on an opposing front ring. If this is the case and the next thing is not true it is a chainline issue but unlikely in every rear position. If it is rubbing on the der. in every position then the der. alingnment/height is most likely the issue.

Park tool's book or web site is a good resource. I think I would go through the entire front der. install/adjustment process to see if it is resolved.

Chain rub in every cog? First if you have a work stand or indoor trainer put it in and see if it really is chain rub. When I think of chain rub I'm thinking chain on an opposing front ring. If this is the case and the next thing is not true it is a chainline issue but unlikely in every rear position. If it is rubbing on the der. in every position then the der. alingnment/height is most likely the issue.

Park tool's book or web site is a good resource. I think I would go through the entire front der. install/adjustment process to see if it is resolved.


I noticed today it rubs on the middle ring up front and the midle cog in the rear. I KNOW that shouldnt happen!! Also, the chain seems to have alot of slack in it. When I changed it I measured it against the old one but it seems seems "loose".

Some Shimano triples can't feather/trim, but I'm pretty sure newer ones do have this ability (at least 105 and up, Sora doesn't and I don't know about Tiagra). Campagnolo triples = no problem.