Poor shifting performance

[earth]

I have poor shifting from both front and rear derailleurs.

The setup is Ultegra 6700 derailleurs and shifters.

When shifting up from the small chainring to the big ring with the front derailleur it is a case of pushing the lever until the chain attempts to go to the big ring, then pausing the pedal stroke for a moment then continuing the pedal stroke and the chain lifts onto the chainring. If I do not pause the pedaling then it never lifts onto the ring.

Shifting to a smaller sprocket with the rear derailleur is temperamental. Sometime it will shift immediately, sometime the lever will travel through the whole arc with no resistance or click as the indexed derailleur springs to the next sprocket.

The cables don't appear to have any significant resistance but the frame has no cable tension adjusters. I have been told this might be the problem. But before I get some inline tension adjusters and go through the toil of fitting them, can someone tell me whether this is the problem?

 

[rusty bearing]

Without the bike in front of me these would be my best guesses

The front certainly sounds like a simple cable tension problem. I don't have any adjustment inline or otherwise on my 105 front mech. Just drop it into smallest ring and take out any slack by hand at the pinch bolt. You could put an adjuster in if you wanted.

Rear sounds more like a shifter that's getting worn out or gummed up, hence the intermittent problem although you don't say whether the rear mech stays in place or drops back to where it shifted from?
Sounds terrible but try squirting a load of GT85 into the works.

 

[earth]

As far as I know the rear mech stays in place. Neither of these problems happen until I am riding so it is difficult to tell. But the lever offers no resistance as it travels through the entire arc and nothing happens. It is as if something did not engage after the last shift took place.

 

[Globalti]

When was the last time you treated the bike to new cable outers and inners?

This will probably solve the problem.

 

[lpretro1]

Sounds more like the ratchet in the lever is starting to go

 

[fossyant]

How old are the parts, when was the last time a cable was changed. Cables first.

 

[earth]

I took out the slack in the front mech cable when it was on the smallest ring. In doing this the cable which was already frayed at the clamp area broke so I got a new inner and outer. It took a while to work out how to fit the cable through the shifter but I did so and in doing this I think I improved the routing slightly. Went out this morning on a patch of tarmac that was not covered in ice and the front mech shifted to the big ring without any problems. I think I may have solved the problem. Not sure about the rear mech yet.

The only problem is the new gear cable outer is black while the previous Shimano stuff was that silver grey colour. Now it's going to pull my OCD string until I change all the cables.