Is the shifter or Rear Mech on the way out ?

[cyberknight]

Changed the cable on the commuter at the weekend as the shifting has been a bit hit and miss up and down the block , outers less than 3 months old so i blasted them with gt 85 and the cable was running smooth but the shift just feels odd.
Sometimes it will shift fine but most of the time it will really struggle to engage up or down but when the chain reaches the selected cog it sits fine and does not rattle to indicate it needs a tweak of the adjuster.

Stumped !

 

[RecordAceFromNew]

Changed the cable on the commuter at the weekend as the shifting has been a bit hit and miss up and down the block , outers less than 3 months old so i blasted them with gt 85 and the cable was running smooth but the shift just feels odd.
Sometimes it will shift fine but most of the time it will really struggle to engage up or down but when the chain reaches the selected cog it sits fine and does not rattle to indicate it needs a tweak of the adjuster.

Stumped !

Generally you can test an indexed shifter by pulling the inner while you shift (essentially with you hand providing the tension a mech would have provided) and see/measure the cable pull. Any issue with the ratchet mechanism with a sti will become quite apparent.

The other thing is that an inner running smooth in an outer doesn't mean the cabling is fine - e.g. if you have a new outer that is a bit too big or not cut cleanly for the ferrule you will have imprecise/sluggish shifts. Similarly a missing ferrule would not affect an inner running smooth in your hand, but once the inner is under tension within the system it can be a different story.

The other thing I guess is you can have gunged up springs in the mech, or looseness in various hinges, hanger bolt, mech bolt, bent hanger etc.

Another point that might help your identification, is if shifts are only poor going up (i.e. towards smaller sprockets) then it is more likely to be spring/gunge issues (unless you have a low-normal/rapid rise mech for which is opposite) since those shifts are driven by the mech's springs rather than your finger.

 

[cyberknight]

Thanks !
Its pretty dire both ways atm , i have to nearly double shift to change to a bigger sprocket and to a smaller one its misses maybe 25 % of the time and i have to reclick then try a half click back to trim .
I have not had chance to do more checks ,for the new build i have found some claris shifters nearly new on the ctc forum so it will be new cables, outers and shifter so the only thing left will be the rear mech which feels fine .

 

[RecordAceFromNew]

Its pretty dire both ways atm , i have to nearly double shift to change to a bigger sprocket and to a smaller one its misses maybe 25 % of the time and i have to reclick then try a half click back to trim .

Dire both ways can mean cable wrongly clamped at the mech, which will deliver a different pull to what the mech expects. Unfortunately this is just another one of many possibilities...

 

[cyberknight]

Righto.
Cable clamped right
cable runs smoothly in outers when unclamped
shifter seems to pull the right amount of cable both ways
Took the jockey wheels off and cleaned /greased them and replaced the bottom one just in case, gave derailleur a good clean and does not feel loose
Reassembled and check the high/low stops When you get it to index to bigger it is sluggish to go smaller or jumps 2
When indexed spot on for smaller is really struggles to go bigger
Or just really sluggish both ways.

Just seems to be no sweet spot even with quarter turns on the barrel adjuster i cant get it spot on .

 

[Crankarm]

I share your pain CK. What group set rear deraillieur, cassette, shifter, cables outer and inner?

I recently put on a whole new rear mech Tiagra, new 9spd Ultegra cassette, new chain Hg53, new shifter 9 spd XT and brand new cable inner and outer all greased, high and low limits fine then indexed all the gears fine - spot on on the Park work stand and test ride, but two weeks later on the road the change is crap so much so it is really annoying now sometimes not changing at all with one click then sometimes jumping two sprockets. The old Tiagra deraillieur and 8 spd shifters worked a treat each time and every time. Moral of the story - if it ain't broke don't fettle it.

 

[cyberknight]

2300 group set with sora RD, jag wire cables +outers
All i did was put a new cassette and chain on ( chain measured against old ) , kmc chain and feck knows 12-25 8 speed cassette and its not been right since and getting worse .

 

[gbb]

Re-seat your back wheel, make sure its straight.
I had this once, spent ages tuning a RD that just wouldnt play ball.
Just happened to take out the wheel, put it back, one more tune...bingo.
I guess in my case, the chain wasn't meshing correctly with misaligned cogs.
Worth a lookee ?

 

[cyberknight]

Re-seat your back wheel, make sure its straight.
I had this once, spent ages tuning a RD that just wouldnt play ball.
Just happened to take out the wheel, put it back, one more tune...bingo.
I guess in my case, the chain wasn't meshing correctly with misaligned cogs.
Worth a lookee ?

Tried that already , thanks anyway for the suggestion.

 

[Garethgas]

Obviously, it's hard to say without seeing it but I would suggest that if you've checked all the above advice then it must surely
be a cable tension issue.
If the rear mech can complete it's travel by you pulling and releasing the cable, then I would be definitely be looking at the
tension.
Please let us know how you get along though

 

[screenman]

Only scanned the topic, but I cannot see where anyone has written an one obvious reason and that is rear mech hanger alignment. I have checked a lot of bikes since I got the tool, not one has been straight yet, the difference between bent even slightly and true is huge on your gear changes.

 

[cyberknight]

Off to the LBS later,probably something simple but its driving me nutty (er) !
Just need to fix the sticky brakes on the subway now doh ! , dont fancy leaving the boardman at work on night shift next week .

 

[cyberknight]

Well picking it up in a bit £12 it cost to fix, sometimes it pays to know the guy there whos a club member who squeezed it in and saves whats left of my sanity as i have limited time and patience after work and kids etc .
I will post what it was later when i have found out .

 

[SatNavSaysStraightOn]

@cyberknight hope you have it sorted.... I had something similar with my 2300 shifters which took months to track down & sort out.

How stiff is the shifter to move? especially the 28 going down to 11 direction.... that was the worst for me. Turned out that everytime I looked at the gear cable (which as fine) it cleared for a day or two and then came back again... It screwed the indexing up as well, so my gears were starting to slip or the standard press twice and then back for 1 gear change routine.
Spraying the actual shifter (inside) with wd40 worked miracles overnight - literally. Turned out the shifter needed greasing inside... just a random thought for you...

Like you I was going mad with it and had come down to the shifter or the rear mech being the cause...

 

[cyberknight]

Cable by RD , felt smooth enough but obviously enough to jigger it !
Proves that doing it when your awake rather than at the end of the day all matters , feel a bit thick now ...............








Well thicker than normal but shift work kills brain cells
http://www.bbc.co.uk/news/health-26630647