Shimano 105 issue
Discussion
Maybe an easy fix maybe not; I can’t get the chain to slip onto the two smallest cogs at the back, up and down on the other rings seems ok. I flooded the shifter with degreaser like the internet told me but still no joy and I would have thought if it was a hardened grease issue the other rings would be problematic. Any suggestions or is a visit to the LBS in order? Thanks.
When was it last serviced? Probably needs re-indexing and if the cables are horribly old, a new gear cable as well. It could be the limit screws, though has it shifted onto the two small cogs previously? If so, that's unlikely.
Plenty of videos if you want to try yourself rather than pay the LBS eg
https://www.youtube.com/watch?v=wie-Shx4YT4
Plenty of videos if you want to try yourself rather than pay the LBS eg
https://www.youtube.com/watch?v=wie-Shx4YT4
Edited by Harpoon on Monday 8th March 17:29
As above I suspect the rear derailleur needs setting up.
I recommend the Park tool website and video guides due to the effort they have gone to to show exactly what you're doing and why.
https://www.parktool.com/blog/repair-help/rear-der...
https://www.youtube.com/watch?v=UkZxPIZ1ngY&ab...
I recommend the Park tool website and video guides due to the effort they have gone to to show exactly what you're doing and why.
https://www.parktool.com/blog/repair-help/rear-der...
https://www.youtube.com/watch?v=UkZxPIZ1ngY&ab...
Plenty of online guides but if we’re you I would...
- Take the mech and chain off and clean it properly so it’s shiny.
- Clean the cassette so it’s shiny
- Fit new cables (optional if you really can’t be bothered but it will help)
- Fit the mech back on and set the lower and upper limits using the screw (follow one of the many online guides)
- Put the chain back on
If it still doesn’t work, drop it off at the LBS.
Cleaning and refitting it will do no harm
At all.
- Take the mech and chain off and clean it properly so it’s shiny.
- Clean the cassette so it’s shiny
- Fit new cables (optional if you really can’t be bothered but it will help)
- Fit the mech back on and set the lower and upper limits using the screw (follow one of the many online guides)
- Put the chain back on
If it still doesn’t work, drop it off at the LBS.
Cleaning and refitting it will do no harm
At all.
I had a similar problem last week on an Ultegra groupset. After cleaning the drivechain to make the rear derailleur work correctly I put the bike on the bike stand and oiled all the pivot points on the rear derailleur and then ran the rear derailleur up and down the cassette “assisting” it on and off the two smallest cogs by hand (be careful with fingers!) and after 5 or 6 cycles up and down the cassette it started working correctly without assistance. I then oiled all the pivot points again and it has worked correctly since. Probably not the best lube for the job but I used ceramic chain lube as it was all I had available at the time.
gazza285 said:
Happens all the time on my CX bike, new cables usually solves the issue.
This.....If it’s not dropping onto the smallest gears, then cable stiction is higher than the spring force in the derailleur. That’s why it won’t shift down, presuming it’s adjusted correctly elsewhere.
Fit a new cable and that should sort it.
I had exactly the same problem on one of my bikes. I fitted a new cable (polymer coated) and the shifting was transformed.
my mate has a Trek Madone and it still has the dork disc fitted after years of owning it!Gary29 said:
Sounds like a dork disc could actually be handy in this case though if he starts adjusting his derailleur without knowing what he's doing!
Just had to Google ‘dork disc’, who knew! I’m just glad I took the pink streamers off the handlebars now, before posting; and just because I’m incompetent doesn’t mean I know what I’m doing. Bike will be going to LBS, where no doubt I’ll get laughed at behind my back
Dnlm said:
Hard-Drive said:
Dork disc! 
Rotor warning label!
Get your LBS to remove those while it's with them!
Wouldn't be saying that if you'd noticed the 10+ saws in the background!!Rotor warning label!
Get your LBS to remove those while it's with them!
iansp said:
I had a similar problem last week on an Ultegra groupset. After cleaning the drivechain to make the rear derailleur work correctly I put the bike on the bike stand and oiled all the pivot points on the rear derailleur and then ran the rear derailleur up and down the cassette “assisting” it on and off the two smallest cogs by hand (be careful with fingers!) and after 5 or 6 cycles up and down the cassette it started working correctly without assistance. I then oiled all the pivot points again and it has worked correctly since. Probably not the best lube for the job but I used ceramic chain lube as it was all I had available at the time.
Ditto. I had to do exactly this on my ultegra. In my circumstance though, it wouldn't even go to the smallest cog with no cable. I noticed during a drivetrain clean.Could be something as simple as cable stretch or slack - that really would be embarrassing to take a bike in for.
Change until you can't go any higher(smallest sprocket) loosen the cable bolt and pull cable through tighten the bolt and try again
I was struggling with my new ultra derailleur recently - what idiot decided to site the cable bolt underneath
Change until you can't go any higher(smallest sprocket) loosen the cable bolt and pull cable through tighten the bolt and try again
I was struggling with my new ultra derailleur recently - what idiot decided to site the cable bolt underneath
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