Claris Front Derailleur

[BrynCP]

I have been having problems with a Claris front derailleur and shifter. This is on a Giant Defy 5 and is the standard type shifter not the thumb one.

It has never shifted properly from new, so I tried to adjust it using the videos/guides/Shimano docs, however the shift from small to large feels wrong, the chain appears to push against the large ring and jam a little before shifting up.

When reading the Shimano docs, it appears there are 4 positions: Small, Small Trim, Large Trim, Large

It then goes on to appear to show that shifting from Small to Large should go: Small, Small Trim, Large, i.e. only 3 lever movements. In the other direction similar, Large, Large Trim, Small. Is my interpretation of the document correct? http://si.shimano.com/php/download.php?file=pdf/dm/DM-GN0001-09-ENG.pdf



If it is, the shifter appears to shift from Large to Small exactly as described, 3 clicks. However, going from Small to Large is 4 clicks. What is wrong?

 

[Nigelnaturist]

It should shift up in one movement as you will pass the trim position on a full movement, i.e. if on the extreme left, it will pass the lower trim position. Measure the cage as it passes over the the lar ring, it should be no more than 2mm, also the angle of the FD to the rings, it should be parallel, it is possible the cage may be slightly bent.

 

[BrynCP]

It should shift up in one movement as you will pass the trim position on a full movement, i.e. if on the extreme left, it will pass the lower trim position. Measure the cage as it passes over the the lar ring, it should be no more than 2mm, also the angle of the FD to the rings, it should be parallel, it is possible the cage may be slightly bent.

By full movement do you mean a deliberate push on the lever all the way to the right through all the clicks? By this I mean when shifting down, just a tap on the level will go right through the trim, it's not even possible when shifting down to make it land on the left/small trim which is exactly what the document above appears to show should be the case. An interesting point is the shifter is incredibly stiff, I ride a 105 and it's not stiff at all and trims fine.

The bike, which isn't mine, has only done about 30 miles from new. The owner couldn't ride it due to illness shortly after they bought it, so missed their chance for a "free" service which is why I am trying to help.

I will look at the cage as you say, I have assumed the shop set that up right so haven't checked it.

 

[Nigelnaturist]

Trying to think about shifting down the rings on my 105 triple, I think if you push it all the way to the right (thats the paddle lever) even in right of the two trim position it should move down, and one swing to the right will move it up a ring again no matter which trim position, I know that when I drop a ring I am almost always in the left trim position, which would be right as I would tend to be in the lower rear gears, and this would put the trim in the correct position, and like wise the other way, I only have 12th gaps on the front so its not as extreme as a 50/34 (50/38/26)

 

[themosquitoking]

When changing down from large to small there is no double shift available i don't think, you need to click once for every movement left. Moving up you can double shift through a trim into a full change.

 

[Nigelnaturist]

When changing down from large to small there is no double shift available i don't think, you need to click once for every movement left. Moving up you can double shift through a trim into a full change.

So explain how if I am trimmed to the left on my large ring, when I drop down I am to the left trim and not the right, I need to re trim if I move the rear toward the extreme right, and remember I am on a triple,

 

[themosquitoking]

So explain how if I am trimmed to the left on my large ring, when I drop down I am to the left trim and not the right, I need to re trim if I move the rear toward the extreme right, and remember I am on a triple,

Yeah, you're right. I didn't think that through properly. Mostly riding a double now so it's not so often i need to trim back up after shifting down.

 

[Nigelnaturist]

Yeah, you're right. I didn't think that through properly. Mostly riding a double now so it's not so often i need to trim back up after shifting down.

I use the full range on my 38th, though tend to stay away from the large and small (small less so though) as it just about covers most of my riding around here, drop on to the 26th front when I would be on the 24-27 range as I have better cadence control, and the large 50th is really only needed when going down steeper hills.