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Chain slack ... How do I cure

blackstar500blackstar500 Posts: 139
edited November 2018 in Workshop
Hello All

I am currently putting together a bike and my latest problem is that I have is a chain slack ..

Both RD and Chain are brand new.

Firstly I believe I have the correct chain length ( 54 inches) for a 50/34 chainring and 11-28 cassette and if I remove any more link this would damage the chain and RD If I accidentally change to the biggest front and back rings

This slack only occurs on the smallest chainring to last 3 smallest cogs . The RD recoils all thw away (the stopper is present) and definitely the spring has tension

I have tried using the B tension screw .. The screw is all the way in and still have a slack

Any Ideas

Smallest to Smallest Ring
20181113-053641.jpg

Biggest to Biggest Rings
20181113-054042.jpg

Posts

  • david7mdavid7m Posts: 633
    I think you have the wrong length cage on RD.
    Dave
  • slowbikeslowbike Posts: 8,476
    Firstly I believe I have the correct chain length ( 54 inches) for a 50/34 chainring and 12-28 cassette and if I remove any more link this would damage the chain and RD If I accidentally change to the biggest front and back rings
    Interesting - I use 50/34 and a 12-28 on one of my bikes - with shortcage 5700 rear mech and I have no issue with slack.

    The hanger looks different - is that an extender on the hanger?

    Not sure your mech is in full chain tension when in the smallest cog.
    30358027311_88e73b14f1_b.jpg

    See how this one has the cage much more horizontal than yours?
  • slowbike wrote:
    Firstly I believe I have the correct chain length ( 54 inches) for a 50/34 chainring and 12-28 cassette and if I remove any more link this would damage the chain and RD If I accidentally change to the biggest front and back rings
    Interesting - I use 50/34 and a 12-28 on one of my bikes - with shortcage 5700 rear mech and I have no issue with slack.

    The hanger looks different - is that an extender on the hanger?

    Not sure your mech is in full chain tension when in the smallest cog.
    30358027311_88e73b14f1_b.jpg

    See how this one has the cage much more horizontal than yours?

    Apologies it is new 105 r7000 RD and cassette is a 11-28
  • svettysvetty Posts: 1,904
    The mech isn't mounted properly. The direct mount link ( the link between the two silver bolts) should be almost horizontal, pointing backwards - yours is almost vertical.
    FFS! Harden up and grow a pair :D
  • That RD is not mounted right. Take it off and start again.
  • if the rear derailleur B screw is like Ultegra R8000 then you need to make sure the notch is aligned correctly. Should be a simple adjustment.
  • arlowoodarlowood Posts: 2,374
    Where did you get the frame from. From you pic it would appear to have some sort of hanger extension link fitted.

    In the pic that silver disc "thingy" just below where the axle protrudes from the seat stay/ chain stay junction is where your derailleur should be bolted to. There seems to be an additional hanger extender link fitted and you have attached the derailleur to the end of that.

    Remove that link thing and fix the derailleur to the correct mounting point and you should be good to go
  • arlowood wrote:
    Where did you get the frame from. From you pic it would appear to have some sort of hanger extension link fitted.

    In the pic that silver disc "thingy" just below where the axle protrudes from the seat stay/ chain stay junction is where your derailleur should be bolted to. There seems to be an additional hanger extender link fitted and you have attached the derailleur to the end of that.

    Remove that link thing and fix the derailleur to the correct mounting point and you should be good to go

    it is a Bowmans Pilgrims Disc
  • svettysvetty Posts: 1,904
    arlowood wrote:
    Where did you get the frame from. From you pic it would appear to have some sort of hanger extension link fitted.

    In the pic that silver disc "thingy" just below where the axle protrudes from the seat stay/ chain stay junction is where your derailleur should be bolted to. There seems to be an additional hanger extender link fitted and you have attached the derailleur to the end of that.

    Remove that link thing and fix the derailleur to the correct mounting point and you should be good to go
    This is wrong - ignore it!

    The R7000 rear mech is supplied with the option to fit to direct mount frames. As you have a conventional frame the link is needed.

    You need to remount the mech so that the other tab on the link abuts the stop. The link will then point backwards just beyond horizontal. Then adjust the B screw so that the upper jockey is reasonably close to the sprockets.
    FFS! Harden up and grow a pair :D
  • Many Thanks People

    All sorted now ... moving on to next bike build problem


    20181113-194209.jpg

    20181113-194316.jpg
  • Well now the mechs been sorted we can direct our attention to the other hazards, iron left under computer desk and your asking for real trouble in bare feet with that upturned 3 pin plug. :shock: :wink:
  • sandyballs wrote:
    Well now the mechs been sorted we can direct our attention to the other hazards, iron left under computer desk and your asking for real trouble in bare feet with that upturned 3 pin plug. :shock: :wink:
    lol .. fixed
  • New photo of big-big is not at a great angle to judge it, but the rear mech cage looks like it's possibly extended away from the upper section by more than ~45 degrees... Not that we would plan to use big-big, but it might be the chain is maybe ~1 link too short.
    ================
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • New photo of big-big is not at a great angle to judge it, but the rear mech cage looks like it's possibly extended away from the upper section by more than ~45 degrees... Not that we would plan to use big-big, but it might be the chain is maybe ~1 link too short.

    I had the B tension screw all the way in .. when the picture was taken .. I have corrected it
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