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Discussion Starter · #1 · (Edited)
Hi All. I just picked up a new to me (actually used but only ridden a few times) Defy with the 105 group. I was doing some checking of the fine tuning of the FD tonight. As I was checking travel, adjusting the cable, ect and changing between cranks I heard a funny noise from the shifter. Almost like I had snapped the cable. At first I thought I had but it was OK. All is fine and the FD is tuned but something funny is happening with the shifter that I'm not sure should be. When I'm on the larger cog and want to shift to the smaller cog I press on the smaller shifter and I hear it click but not FD doesn't move. If I click the shifter again the FD moves and the chain grabs the smaller cog (almost like it's a shifter for s triple not a double but the FD doesn't really movd). Or if I'm on the large cog and press the smaller shifter all the way all at once it will change to the smaller cog. Is this as designed and my lack or memory of the test ride today plus inexperience with the group set have me all confused?
 

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That is the trim function. There are actually four shifts in that front derailleur. Not two. When you are in the small ring in front with the shifter all the way released...... (first position) as you shift the rear down the cassette into the higher gears, the front derailleur will start to rub the chain on the outer plate. Move the brake/shift lever slightly inboard one small click. This will move the derailleur a very small amount outboard just enough to eliminate the rub. Make your shift to the big ring from this position. The same applies to the big ring. The problem you will have is getting the cable tension set up just right so that you have BOTH trim positions functioning correctly. It may take quite a bit of fiddling if you are not experienced with them. The barrel adjuster comes in handy for this.
 

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Discussion Starter · #3 · (Edited)
That is the trim function. There are actually four shifts in that front derailleur. Not two. When you are in the small ring in front with the shifter all the way released...... (first position) as you shift the rear down the cassette into the higher gears, the front derailleur will start to rub the chain on the outer plate. Move the brake/shift lever slightly inboard one small click. This will move the derailleur a very small amount outboard just enough to eliminate the rub. Make your shift to the big ring from this position. The same applies to the big ring. The problem you will have is getting the cable tension set up just right so that you have BOTH trim positions functioning correctly. It may take quite a bit of fiddling if you are not experienced with them. The barrel adjuster comes in handy for this.
Just to clarify by 4 shifts you mean two up and two down. Right?

The the middle clicks are for fine tuning to keep the FD off the chain?
 

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No. There are two big throw shifts up and down, and there are two very small "trim" shifts both up and down as well. The trim shifts feel very small and imperceptible if you are not used to them. If you don't have your cable tension or limit screws set up properly, one or both of the small trim shifts will do absolutely nothing, and the front derailleur will not move at all. This is hard to explain over the internet, so you may need to take it to a shop. But do this............Shift the front derailleur as far as it will go onto the big ring while in the small cog in the back. Start downshifting the rear to the larger cogs in the cassette. Does the inner plate of the front derailleur start rubbing the chain when you are close to big/big or in big/big? If it does, slightly press the inner paddle of the front shifter until you hear a click. Not a big paddle throw, just a little push. Does the front derailleur move inboard just a couple of millimeters? If it does and the chain rub goes away, that is trim. If it doesn't move inboard slightly your cable tension is wrong. Same applies to the small chain ring.
 

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Ok, you added that last line while I was posting. Now the answer is yes. I think you understand.
 

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Discussion Starter · #6 ·
No. There are two big throw shifts up and down, and there are two very small "trim" shifts both up and down as well. The trim shifts feel very small and imperceptible if you are not used to them. If you don't have your cable tension or limit screws set up properly, one or both of the small trim shifts will do absolutely nothing, and the front derailleur will not move at all. This is hard to explain over the internet, so you may need to take it to a shop. But do this............Shift the front derailleur as far as it will go onto the big ring while in the small cog in the back. Start downshifting the rear to the larger cogs in the cassette. Does the inner plate of the front derailleur start rubbing the chain when you are close to big/big or in big/big? If it does, slightly press the inner paddle of the front shifter until you hear a click. Not a big paddle throw, just a little push. Does the front derailleur move inboard just a couple of millimeters? If it does and the chain rub goes away, that is trim. If it doesn't move inboard slightly your cable tension is wrong. Same applies to the small chain ring.
Ok. I think I get it now. On the shifter there is a gross throw and a trim throw. The gross changes rings and the trim or small throw is more of a trim to get the FD to move slightly to avoid chain rub. Right? On the small paddle it "feels" like two very big clicks whereas on the large paddle the trim is a very small click and the gross movement is very pronounced.
 

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If the problem is solved, great. If not, what year is the bike? When 10 speed 105 first came out, all the front shifters were triples, and you just didn't use one of the positions. They changed it a year or two later, as people were breaking them by inadvertantly shifting partway into the top position which was locked out by the upper limit screw.
 
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