Bicycle Mechanics - Shimano 105 - erratic/non shifting??

I have 105 on my roadbike and lately I have a hard time shifting? It'll take a minimum of 2 shifts before it goes to the next gear. It doesn't feel like the lever is engaging to shift? Is there something wrong in the shift lever? Rear Derailer looks fine.

Cable stretch maybe. How old are the shifters?

This subject has been posted here and other boards several times lately, and I have had the problem with RSX shifters. A generous application of lube into the shifter housing helps. There is an issue with colder weather, but the actual reason for the cold shifting problems has eluded me. I don't have this problem with Shimano shifter pods on my MTB, and those work in a simialar fashion to STI.

It's ABOUt 3 yrs old but I've never overhauled the system and it started happening this past summer. Could it be worn/stretched cables??

also check the cable guides under the BB. Could be dirty/gummed up.

I have 105 on my roadbike and lately I have a hard time shifting? It'll take a minimum of 2 shifts before it goes to the next gear. It doesn't feel like the lever is engaging to shift? Is there something wrong in the shift lever? Rear Derailer looks fine.

All replies so far have been good advice and worth following up on. I would like to add my own to the pile. There are three most common issues when it comes to STI shifter problems. The rear derailluer shifts from smaller cogs to larger ones by the tension and pull of the cable. If the failure or problem is happening in this mode, then clearly look at the cable adjustment. A book that I use (there may be many other approaches, this is but one) instructs you to (for 9 speed Shimano)
1. shift the chain onto the next to smallest rear cog
2. As you turn the crank arm slowly, turn the rear derailluer cable adjusting barrel counterclockwise. This causes the derailluer to start moving the chain towards the next larger cog.
3. Continue the counterclockwise turning until you can hear the chain chattering or clacking as it starts to rub and make contact with the next larger cog.
4. Now, slowly turn the cable adjuster clockwise until you can no longer hear the clacking, chattering noise.

This takes care of most common problem numero uno.

Next, The derailluer is very slow to move from a larger cog to a smaller one. This is just the opposite of the problem fixed by the previous adjustment. This is caused by failure to keep the derailluer cleaned AND lubricated. Not just lubricated, but clean too. I suppose in an extreme case the large return spring could be broken, but I doubt it.

Remove, clean, lubricate, reinstall and adjust the derailluer. That takes care of most common cause numero doce'.

Number three most common would be mechanical problems within the STI shifter. Any given shift position could have the retaining pawl worn and/or dirty and not lubricated. Disassembly, cleaning and lubricating are needed from time to time for the STI shifters. Not often, as they are well protected and covered. If you carefully cover the first two possibilities, and the problem remains, I would take apart the STI shifter, clean, lubricate and put it back together.

You might check this, if other adjustment does not fix it. Loosen the cable at the der. and see if the cable will feed back out of the shifter. i have seen many cables fray right at the cable stop. It will screw up the shifting and you can't see the problem with out slipping the cable out of the shifter. Once it breaks you will be in for some BIG frustration trying to get it and the pieces out of the shifter.

You might check this, if other adjustment does not fix it. Loosen the cable at the der. and see if the cable will feed back out of the shifter. i have seen many cables fray right at the cable stop. It will screw up the shifting and you can't see the problem with out slipping the cable out of the shifter. Once it breaks you will be in for some BIG frustration trying to get it and the pieces out of the shifter.

Good point Rev Chuck. Another thought is that when shifting to larger cogs, the strength of the cable and the mechanical leverage applied by the shifting system, will overcome friction & drag caused by dirty/poorly maintained components. But, if the problem is poor/slow shifting when shifting to smaller cogs, where dirt/friction have their biggest opportunity to screw up the works, I'd also look at the cable housing. In fact if the problem is in shifting to smaller cogs, I'd put this at about #2 or #3 on the list of things to check. The original post gave few clues. But it sounds like not much maintenance, if any has been performed on the shifting system in 3 years. I have been surprised at how much dirt builds up inside that short piece of rear derailluer cable.

seeing this brought attention to a problem that I have had with my right 105 sti, it seems like the same problem I'm having.

I find that every few shifts, when I use the big lever (downshift) the lever goes all the way to the end of its travel without shifting. I feel nothing, and there is no resistance against my hand. When I let it return to the starting position and try again, it works like normal. sparticus1262, was this the same problem that you were having?

My bike is really clean and lubed. My bike is well adjusted, and the drivetrain isn't excessively worn. however, I am still having the problems I just described.

Having the same problem with my STX left shifter pod , seems to be dirt in the works , will probably have to strip and clean .
When did you last change the cables / covers ? Once a year seems about right for most people in dusty / dirty areas . ditto for rain .

I have the same problem with my 105 STI shifters. On the right hand shifter (rear) when I push the small lever to the right, nothing will happen, when I release and try again, it shifts normally. Not for every shift mind you, just every now and then. It seems worse in cold wheather.

How is it possible to take apart these shifters? I thought it impossible...?

What I have tried is removing the shifter from the bar, and dunking it in some degreaser for awhile. Then pouring in some TriFlow lubricant. It SEEMS better, but I haven't tried riding it yet....

Anyone else have fixing suggestions?

Digger

That should have done the trick Digger.

From my experience with Shimano shifter/lever combos is to keep them clean and as dry as possible.

Shimano units are not "serviceable" as one may think. You can take the lever off the bike and flush it with a good cleaner, force air dry it, and then apply some good lube to the mechanism.

Campagnolo is actually fully "serviceable" by means that you can get the pawls and other items to repair a shifter. Shimano sells a shifter module for replacement but don't dare try to disassemble the shift pod. It's better to just get a new shifter.

Depending on the age, mileage and maintenance performed, 3-years is about the life of a shifter. This also depends on the type of riding you do. Lots of shifts, wet, etc.

Check Ebay and there usually are a couple of people that sell just one side of the shifter set for $59 and it's new.

I have taken my pods apart and cleaned them. But, then again, I fix vintage watches for fun. So, if you are not good at putting things back together, don't try it. If you have the ability to put something back together that someone else took apart, you can do it.

I have taken my pods apart and cleaned them. But, then again, I fix vintage watches for fun. So, if you are not good at putting things back together, don't try it. If you have the ability to put something back together that someone else took apart, you can do it.


Errr...I think I'll sat away from that. Like I said, they SEEM better. They ain't that broke yet. :)

Digger