Portis

For some time i have had a bike that i can't make shift reliably on the rear derailleur. I am 99 % sure it is the fault of the shifters or the derailleur or both. I have replaced the inner wire and housing and still i have the symptom.

THe symptom is that sometimes in the bike does not want to downshift when i activate the lever. It shifts fine going to smaller cogs and usually shifts pretty well going to larger cogs but sometimes in the middle of the cluster, i will hit the shifter for a down shift (inward) and it won't go to the next cog. I have to hit the shifter again, almost like friction shifting. (It IS index shifting)

I have tried to increase innerwire tension but that is not the problem. It shifts perfectly going from the outermost cog to the second outermost cog. It is in the middle of the cluster that i have trouble. LIke i said, most of the time it shifts ok but sometimes it just decides that it doesn't want to shift. IOW, sometimes the inward travel of the derailler is not sufficient to make the chain jump to the next inward cog.

Is there a way short of just replacing the shifters and derailler to troubleshoot what might be causing this? I plan to upgrade the derailler at least but not for a little while yet.

Retro Grouch 

STI shifters, right? My guess is they need a good cleaning out. If that's the case, a shot of WD40 and a blast of compressed air will fix it.

Portis

Yes. Shimano EF 29's. I have cleaned them multiple times with WD 40. Still it happens.

neil0502

Sure, you can throw another rear shifter on and see what happens, but:

What makes you say that the innerwire tension--as adjusted at the rear derraileur adjuster ferrule--isn't the problem? Have you also adjusted the tension of the rear shifter wire at the rear shifter? Is the rear derailleur bent?

I would start from scratch, following these instructions, before I bought new shifters:

Site One

Site Two

Portis

I have played with it some more and improved it somewhat by messiing with innerwire tension some more.

I have the instructions from Sheldon's site as well as park tool printed off in a binder that i consult. It still likes to hesitate from time to time but i think i have improved it a bit. One quick question: How critical is it that ALL slack is taken out of the wire before it is secured to the anchor bolt, prior to indexing adjustment?

I noticed that the cable end was not completely seated in the shifter housing when it was in the most relaxed postion. IOW, i needed to take the pliars and pull on the wire to seat it harder into the shifter housing, before securing the anchor bolt.

neil0502

I take out all the slack before securing it. We're not talking gorilla pull here--just taking out the slack.

Perhaps as important, though, is ensuring that you're routing it around the anchoring bolt properly. Make sure you keep the cable running on the inboard side of the fixing bolt, not the outboard side. Does that make sense? I've seen bikes where that simple issue can cause a shifting issue--primarily skipping--in the middle cogs.

You are adjusting the rear der in your little (or middle) ring, little cog combination, right?

Portis

Yes. I am using the middle/outer combo. I believe the cable to be routed correctly. It is the same way i have always done it, and i have an identical bike that functions properly to look at, and i routed it the same way.

I am leaning towards my shifters. These shifters click when you push on the thumb and then it is supposed to shift. However, there is still a LOT of travel left after they click. Generally if the chain doesn't shift inward after the click, i have to just push it farther inward. It will then usually go ahead and shift. Sometimes it requires two strokes on the lever. It is also possible to shift more than one cog with one lever stroke.

Maybe i am just trying to get them to perfect, but i know they can shift better. As far as most index adjusting procedures are described, it generally has you just adjust it so it shifts well from the outermost to the second outermost cog and once that is accomplished, it is supposed to be good for the other cogs. Not so with my setup.

neil0502

Smooth, crisp shifts are a worthwhile goal. Seems like you've ruled out most of the other likely culprits. Maybe a new shifter is the right thing to do.

Good luck!