shifting problem

shiznit76
shiznit76 Posts: 640
edited March 2019 in Workshop
Hi, when my chain is on the big ring at front it slips up the cassette to largest sprocket, but coming back down it hesitates on the 10th and 9th sprocket (11sp shimano ultegra). It seems to move freely when on smaller ring at front, just on the big ring the problem occurs. It is a case of cable tension? The chain was replaced about 500 miles ago so don't think that is the problem
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Comments

  • First.Aspect
    First.Aspect Posts: 14,630
    Chain tension too high? Try the b limit screw.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    picture of chain please
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • picture of chain please
    A picture of the chain?? It's just normal chain
  • Chain tension too high? Try the b limit screw.
    And do what? I'm not well versed in these things
  • pilot_pete
    pilot_pete Posts: 2,120
    Could be any number of things from B tension (which sets the distance from the top jockey wheel to the top sprocket), to indexing (which could be ever so slightly out which is manifesting itself on that one shift, to a bent derailleur hanger (you need to check it with a tool as it can look perfectly straight to the eye and not be), to cable inner having a kink, to a problem with the cable outer (dirt, corrosion, a burr where it was cut, a bad cable run, a badly seated end stop etc etc) through to a problem in the shifter or with the derailleur itself. Maybe even a problem with the chain, or the cassette which could be worn.

    So you can see, with the info supplied it is simply too difficult to diagnose correctly on here. Pictures would help, video of the shifting may too...

    PP
  • Pilot Pete wrote:
    Could be any number of things from B tension (which sets the distance from the top jockey wheel to the top sprocket), to indexing (which could be ever so slightly out which is manifesting itself on that one shift, to a bent derailleur hanger (you need to check it with a tool as it can look perfectly straight to the eye and not be), to cable inner having a kink, to a problem with the cable outer (dirt, corrosion, a burr where it was cut, a bad cable run, a badly seated end stop etc etc) through to a problem in the shifter or with the derailleur itself. Maybe even a problem with the chain, or the cassette which could be worn.

    So you can see, with the info supplied it is simply too difficult to diagnose correctly on here. Pictures would help, video of the shifting may too...

    PP


    Sounds like a job for lbs.
    For info, it isn't cassette as it happens with two dfferent ones, tried another wheel and problem is the same so can at least rule that out
  • photonic69
    photonic69 Posts: 2,417
    Have you checked the indexing? Follow the always excellent Park Tool video help guides:

    https://youtu.be/UkZxPIZ1ngY

    Could be a simple adjustment is all you need.


    Sometimes. Maybe. Possibly.

  • PhotoNic69 wrote:
    Have you checked the indexing? Follow the always excellent Park Tool video help guides:

    https://youtu.be/UkZxPIZ1ngY

    Could be a simple adjustment is all you need.

    cheers, will give it a go.

    If was indexing would it not occur on both chainrings?
  • photonic69
    photonic69 Posts: 2,417
    shiznit76 wrote:

    cheers, will give it a go.

    If was indexing would it not occur on both chainrings?

    Not necessarily as chain tension and chainline are different in either chainring

    It's also free :D


    Sometimes. Maybe. Possibly.

  • pilot_pete
    pilot_pete Posts: 2,120
    shiznit76 wrote:
    Pilot Pete wrote:
    Could be any number of things from B tension (which sets the distance from the top jockey wheel to the top sprocket), to indexing (which could be ever so slightly out which is manifesting itself on that one shift, to a bent derailleur hanger (you need to check it with a tool as it can look perfectly straight to the eye and not be), to cable inner having a kink, to a problem with the cable outer (dirt, corrosion, a burr where it was cut, a bad cable run, a badly seated end stop etc etc) through to a problem in the shifter or with the derailleur itself. Maybe even a problem with the chain, or the cassette which could be worn.

    So you can see, with the info supplied it is simply too difficult to diagnose correctly on here. Pictures would help, video of the shifting may too...

    PP


    Sounds like a job for lbs.
    For info, it isn't cassette as it happens with two dfferent ones, tried another wheel and problem is the same so can at least rule that out

    Ok, so you have ruled out cassette, that’s good. Now if you want help and to avoid a trip to your lbs, you need to give us a chance with pictures and/or video. Pictures of the rear derailleur and cassette from behind, especially in the offending gears, a picture of the top jockey wheel and biggest cog to see what your B tension adjustment looks like etc.

    It is all about elimination of various possibilities as you have done with the cassette. You will eventually trace the root cause, or alternatively just take it to your lbs. However, if it is not obvious to them then it could cost you a fair bit more as they just replace parts trying to find the culprit. Without more info/ pictures we are just speculating...

    PP
  • Pilot Pete wrote:
    shiznit76 wrote:
    Pilot Pete wrote:
    Could be any number of things from B tension (which sets the distance from the top jockey wheel to the top sprocket), to indexing (which could be ever so slightly out which is manifesting itself on that one shift, to a bent derailleur hanger (you need to check it with a tool as it can look perfectly straight to the eye and not be), to cable inner having a kink, to a problem with the cable outer (dirt, corrosion, a burr where it was cut, a bad cable run, a badly seated end stop etc etc) through to a problem in the shifter or with the derailleur itself. Maybe even a problem with the chain, or the cassette which could be worn.

    So you can see, with the info supplied it is simply too difficult to diagnose correctly on here. Pictures would help, video of the shifting may too...

    PP


    Sounds like a job for lbs.
    For info, it isn't cassette as it happens with two dfferent ones, tried another wheel and problem is the same so can at least rule that out

    Ok, so you have ruled out cassette, that’s good. Now if you want help and to avoid a trip to your lbs, you need to give us a chance with pictures and/or video. Pictures of the rear derailleur and cassette from behind, especially in the offending gears, a picture of the top jockey wheel and biggest cog to see what your B tension adjustment looks like etc.

    It is all about elimination of various possibilities as you have done with the cassette. You will eventually trace the root cause, or alternatively just take it to your lbs. However, if it is not obvious to them then it could cost you a fair bit more as they just replace parts trying to find the culprit. Without more info/ pictures we are just speculating...

    PP


    Cheers, I'll need work out how to post these first
  • ok, got video and photos, but how do i attach them here?
  • cooldad
    cooldad Posts: 32,599
    From a hosting site. Read the FAQs up there ^^^^^^^
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • I'm on my phone Can't see a FAQ section. I take it there is no way to just paste photos in?
  • cooldad
    cooldad Posts: 32,599
    Nope.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • Matthewfalle
    Matthewfalle Posts: 17,380
    shiznit76 wrote:
    picture of chain please
    A picture of the chain?? It's just normal chain

    you're missing the point here, aren't you?
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • pilot_pete
    pilot_pete Posts: 2,120
    Upload your photos to a hosting site, such as https://imgbb.com/ and then paste the links to each photo in this thread. :wink:

    PP
  • pilot_pete
    pilot_pete Posts: 2,120
    Ah, ok, posted at the same time.

    From the video, the angle you have filmed it at is not directly behind the problem shifts, but it looks like two things from what I can see.

    1. The upper jockey wheel looks very close to the bigger sprockets, it is a bit hard to tell as it needs to be as close as possible without the chain being fouled between the jockey wheel and the sprocket. Adjust the B tension screw with the chain on the biggest sprocket.

    Being too close can cause that issue as the chain gets trapped between the bigger cogs and the top jockey wheel, which prevents it from changing into the next smaller cog cleanly.

    2. The indexing could be slightly out, again, can’t tell without a view directly behind the derailleur, rather than at an angle like in your video.

    If the B screw adjustment and indexing doesn’t sort it I would suggest checking the hanger alignment. You will need a tool for this or get your lbs to check it for you.

    Good luck

    PP

    Oh and p.s. the problem cogs are the 2nd and 3rd aren’t they, not the 10th and 9th...
  • pilot_pete
    pilot_pete Posts: 2,120
    If you are unsure about B tension adjustment, look in the dealer manual for your particular Ultegra model here https://si.shimano.com/#/en/search/Series?name=ULTEGRA&generation=6800&type=ROAD

    PP
  • pilot_pete
    pilot_pete Posts: 2,120
    To see the B tension adjustment you need to put it in the little chainring on the front and the biggest cog on the back and take a picture side on, and/or a video of you pedalling it backwards. Those two pictures show little of use.

    For indexing, the pictures need to be from directly behind to see if the chain comes off the sprocket and goes around the top jockey wheel perfectly vertically, I.e. if you had no chain on we need to be able to see if the top jockey wheel is directly below and in line with the cog in question. Does that make sense?

    To be honest, look in the dealer manual (from that link pick the version of Ultegra you have and look for the manual prefixed RD (for rear derailleur)). Then, follow the instructions for setting the B screw tension. If you simply turn the adjuster to pull the chain (well, the top jockey wheel actually) away from the biggest sprocket and see if that improves the shift. I’m guessing here from your first video that the chain is getting trapped as the top jockey wheel looks like it is set too close to the biggest cog.

    PP
  • photonic69
    photonic69 Posts: 2,417
    Follow the Park Tool guide first and get it indexed properly. Then if you've still got problems post back here. Hangers can be quite out of true yet it will still shift reasonably well if a little suboptimal.


    Sometimes. Maybe. Possibly.

  • pilot_pete
    pilot_pete Posts: 2,120
    Pictures like this;

    B9-D6-CFAC-C135-4-AB4-84-E8-B99-BD4491-E41.jpg

    See how the view is directly behind the selected gear/ chain line? Can you see that the chain is running perfectly vertical off the cassette cog an round the top jockey wheel? The chain is not being pushed towards the next biggest cog, or driven towards the next lower cog. That means each shift will keep the chain exactly aligned off each cog. That shows the indexed position.

    D66189-A6-EED6-48-AE-BB14-10322794-CE07.jpg

    This picture shows the gap between the chain coming off the biggest cassette cog and wrapping around the top jockey wheel with the chain on the small chainring up front. You can see that the chain is not jammed between the cog and the jockey wheel. The B tension adjustment is used to make sure that the top jockey wheel is as close to that big cog as possible without trapping the chain. That makes for the snappiest shifting. I suspect your top jockey wheel is too close to the cog.

    PP
  • photonic69
    photonic69 Posts: 2,417
    A) have you indexed it?

    B) you need to photograph it directly from behind inline with the sprocket it is in

    It's doesn't look like the hanger is badly bent


    Sometimes. Maybe. Possibly.

  • PhotoNic69 wrote:
    A) have you indexed it?

    B) you need to photograph it directly from behind inline with the sprocket it is in

    It's doesn't look like the hanger is badly bent


    It shouldnt be bent at all, relatively new and never been banged
  • photonic69
    photonic69 Posts: 2,417
    If it's that new then it must be a cable tension/indexing issue

    It looks like the bike is in a turbo? Perfect to index it all in 10 minutes using the video. Release pressure on Turbo roller First.


    Sometimes. Maybe. Possibly.

  • PhotoNic69 wrote:
    If it's that new then it must be a cable tension/indexing issue

    It looks like the bike is in a turbo? Perfect to index it all in 10 minutes using the video. Release pressure on Turbo roller First.

    Well, it's a year old, but been kept in good condition and never banged, only seems to have happened recently and has been on the turbo all winter