problem trimming Shimano 105s
 

I have a 2001 Trek 2000 with new Shimano 105 Flightdeck shifters cabled to a front Tiagra 9 speed derailleur over a triple Chain ring and rear 105 derailleur over a 9 speed cassette. I am unable to trim the front derailleur. I get 3 solid clicks and instantaneous jumps from the smallest ring to the middle and middle to top. But I need to trim when riding in the middle chainring. With my old 105 shifter, I was able to do that by gently pressing the smaller lever after an up shift until it clicked back to an intermediate detent. I have seen the mechanic at the local shop trim the new shifter although even he could not do it consistently but I have not succeeded even once.
Are there any internal adjustments to these shifters or anything I can adjust on the derailleur?
Any tricks to trimming with these shifters?

There is nothing in the shifter. Too tight limit screws and/or too tight cable tension can hose the trim function.You know how it's suppose to work,so operator error doesn't seem to be a factor.

I'm curious as to what effect limit screws would have on trimming the middle chainring? Or, are you just making a general statement?

Just generalizing. So maybe the shifter is hosed?

For the middle ring there should be two click stop positions you can use for trimming. If you don't have those it may mean that the cable was not all the way out of the shifter when the cable was attached to the front derailleur. With the cable detached from the derailleur the small shift lever should be flipped several times while pulling the free end of the cable. You can find this in the Shimano instructions. Pull the slack out of the cable when attaching it to the derailleur. If there is any problem shifting to the big ring you can add tension to the cable with the barrel adjustor. With the cable all of the way out the derailleur shoud be positioned for the smallest chain ring. As you operate the brake lever shifter you should have 3 full clicks for a total of 4 full positions. The 4th position is for the big ring. The 2nd and 3rd positions can be used to trim the middle chain ring, they should be slightly to the left and right of the middle ring. The 3rd position can be used to trim the big ring. Depending on the generation of shifters you may also have a soft click or half click available for trimming from the left most position.

Al

I'm assuming his shifter is ok, as he says it's new. I have a couple of 105 set-ups and agree that cable tension can effect the FD trimming. The other thing I would question is the cable. Is it new? Is it possibly sticking in the middle of the range? If the middle ring trimming is only a problem going in one direction, then I would be suspicious of the cable sticking (or maybe the routing). Just some thoughts ...... Good luck, Nathan.

Thanks for the suggestions. This gives me some hope.
Is there somewhere you can suggest for those Shimano instructions. The shifters were installed by the local bike shop and I have no instructions for redoing the installation.

I found installation instructions for the 2004 models at the Shimano European web site:

http://cycle.shimano-eu.com/media/cy...9830538365.pdf

You can find similar instructions for shifters and a lot of other components at http://www.parktool.com.

Al