Advertise on Bikeforums.net



User Tag List

Results 1 to 23 of 23
  1. #1
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Di2 dropping chain?

    If anyone here is familiar with Di2, I could use some help. I have had my bike for about 4 months now and I LOVE it however, if I am in the big ring and come to a stop as soon as I start to pedal again the chain drops down to the small ring. I have taken it in to the lbs and they have done all the adjustments. They can't replicate it on the stand. I guess my question is, is this something I am causing or is it the equipment? I had 105 before and rarely dropped my chain. The bike store has only sold 3 Di2 equipped bikes, so they are new to this as well and they have tried to help. I would say this happens about 75% of the time. Any ideas?

  2. #2
    biked well well biked's Avatar
    Join Date
    Jul 2005
    Posts
    6,883
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Are you sure you're not accidentally hitting the front shift button while you're stopped or as you're starting?

  3. #3
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by well biked View Post
    Are you sure you're not accidentally hitting the front shift button while you're stopped or as you're starting?
    I don't think so, but it is certainly possible. I am going to pay more attention tomorrow and see if that is it.

  4. #4
    Biking Viking. goatalope's Avatar
    Join Date
    Nov 2007
    Location
    Camp Hill, PA
    My Bikes
    '01 Lemond Buenos Aires, '11 Specialized Stumpjumper FSR, 70s Austro Daimler Inter 10, 80s Motobecane Mirage 10 Fixed Gear
    Posts
    305
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It knows you need a lower gear. Do not question it.

    Alternatively, has your bike shop given it a test ride to recreate the problem? A lot of stuff happens on the road, but not the stand.
    Tuesdays I work on my hair helmet.

  5. #5
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    No, I don't think they have tried to ride it. I thought it was possibly from moving my pedal backwards as I start out, but I have stopped doing that and it will still drop down. I do probably need the lower gear, I just thought I needed to shift it myself to get to it. It has been so amazing other than this, that I feel guilty for even having a complaint at all....

  6. #6
    7-speed doomsday prepper ThermionicScott's Avatar
    Join Date
    Aug 2011
    Location
    CID
    My Bikes
    1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX
    Posts
    8,943
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)
    Uh-oh, the machines are revolting earlier than expected...
    Quote Originally Posted by chandltp View Post
    There's no such thing as too far.. just lack of time
    RUSA #7498

  7. #7
    Senior Member himespau's Avatar
    Join Date
    Jun 2008
    Location
    Louisville, KY
    Posts
    7,721
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ThermionicScott View Post
    Uh-oh, the machines are revolting earlier than expected...
    Something to keep in mind.
    Punctuation is important. It's the difference between "I helped my uncle, Jack, off a horse" and "I helped my uncle Jack off a horse"


  8. #8
    bike whisperer Kimmo's Avatar
    Join Date
    Dec 2009
    Location
    Melbourne, Oz
    My Bikes
    copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
    Posts
    6,842
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by nrgy View Post
    I do probably need the lower gear, I just thought I needed to shift it myself to get to it. It has been so amazing other than this, that I feel guilty for even having a complaint at all....
    IMO that's a feature, not a bug.

  9. #9
    Senior Member
    Join Date
    Sep 2004
    Location
    boston, ma
    Posts
    2,841
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    big ring and what cogs in the back? towards the larger ones? does the derailer physically move or the chain just falls?

  10. #10
    Senior Member
    Join Date
    Aug 2009
    Location
    Houston, TX - Energy corridor
    My Bikes
    2011 Trek SOHO Deluxe, and 2010 Specialized Roubaix Expert
    Posts
    867
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I upgraded my Ultegra 6700 to Di2. I did the install and it was easy. The shifts have been flawless. The front derailleur shifts so fast and easy.

  11. #11
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    22,556
    Mentioned
    69 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by nrgy View Post
    If anyone here is familiar with Di2,
    You don't need a mechanic, you need an electrician.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  12. #12
    Constant tinkerer FastJake's Avatar
    Join Date
    May 2010
    Location
    Madison, Wisconsin
    Posts
    6,121
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I thought electronic shifting was supposed to be perfect and foolproof? Maybe the shop didn't properly seat the ends of the cable housing

    Sorry I don't have any actual help to offer...
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  13. #13
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    22,556
    Mentioned
    69 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by FastJake View Post
    I thought electronic shifting was supposed to be perfect and foolproof?
    It almost is, but fools are too ingenious.

    Seriously, I'd suspect some kind of contact problem. Possibly when starting out you flex the lever body or something like that causing a signal to the FD. I don't know the wiring logic of Di2 so can't say whether you're looking at a normally open which is shorting, or a normally closed which is breaking contact.

    If the dealer can't help or duplicate the issue, I'd call Shimano in California. They did a lot of Beta testing here in the USA, and someone there might already have encountered the problem.
    Last edited by FBinNY; 05-15-12 at 11:50 PM.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  14. #14
    Senior Member Jed19's Avatar
    Join Date
    Oct 2004
    Posts
    3,898
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    It almost is, but fools are too ingenious.
    Man, I love this quote
    Regards,

    Jed

  15. #15
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the suggestions. I am going on a 30 mile ride this morning so I will pay closer attention to what I am doing when it happens.

  16. #16
    Nobody mconlonx's Avatar
    Join Date
    Jun 2007
    Posts
    5,484
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    Could be the high limit screw on the FD is a bit too tight. Also could be the lateral alignment is not set up correctly.

    If this happens when you start from a start, I'd assume that you are in the lower gears/larger cogs out back at the time. That crosschain type of situation could cause it, if you backpedal at all in one of the lower gears -- FD will auto-trim toward the inside, facillitating the unwanted downshift.

    Could also be Shimano trying to retrain you with your shifting. When approaching a stop, instead of shifting into a lower gear out back, consider shifting into the small ring up front...
    I know next to nothing. I am frequently wrong.

  17. #17
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mconlonx View Post
    Could be the high limit screw on the FD is a bit too tight. Also could be the lateral alignment is not set up correctly.

    If this happens when you start from a start, I'd assume that you are in the lower gears/larger cogs out back at the time. That crosschain type of situation could cause it, if you backpedal at all in one of the lower gears -- FD will auto-trim toward the inside, facillitating the unwanted downshift.

    Could also be Shimano trying to retrain you with your shifting. When approaching a stop, instead of shifting into a lower gear out back, consider shifting into the small ring up front...

    I think this is it! I figured it was operator error When it would drop, I was in the larger cogs (usually the second or third one down). If I am in the middle of the cassette it does not drop. Thanks for your help, I appreciate it.

  18. #18
    Si Senior dbg's Avatar
    Join Date
    Nov 2004
    Location
    Naperville, Illinois
    My Bikes
    Too Numerous (not)
    Posts
    2,444
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by reptilezs View Post
    big ring and what cogs in the back? towards the larger ones? does the derailer physically move or the chain just falls?
    Good questions. Have we established that the FD is actually moving and performing an active shift. Or is the adjustment just so close that the extra torque from standing start causes it to slip down on its own?
    David Green, Naperville, IL USA "The older I get, the better I used to be" --Lee Trevino

  19. #19
    Si Senior dbg's Avatar
    Join Date
    Nov 2004
    Location
    Naperville, Illinois
    My Bikes
    Too Numerous (not)
    Posts
    2,444
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by nrgy View Post
    I think this is it! I figured it was operator error When it would drop, I was in the larger cogs (usually the second or third one down). If I am in the middle of the cassette it does not drop. Thanks for your help, I appreciate it.
    I stiil don't think it should shift on its own no matter where you have it (even big-big, God forbid).
    David Green, Naperville, IL USA "The older I get, the better I used to be" --Lee Trevino

  20. #20
    Must... ride... more... Phil_gretz's Avatar
    Join Date
    Aug 2009
    Location
    Sterling, VA
    My Bikes
    '77 Fuji S-10S, '82 Fuji Team, '88 Fuji Saratoga, '08 Scattante CFR, '12 Jamis Sputnik, '13 Motobecane Fantom29 HT
    Posts
    2,395
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dbg View Post
    Good questions. Have we established that the FD is actually moving and performing an active shift. Or is the adjustment just so close that the extra torque from standing start causes it to slip down on its own?
    That's my question. Is the FD moving as though in response to a command to shift down? Or is the crankset effectively flexing, causing the chain to hit the FD cage and be pushed off of the large ring? Does the OP always push off with left and pedal with the right to start? Does this behavior happen when starting with the left foot?

  21. #21
    Must... ride... more... Phil_gretz's Avatar
    Join Date
    Aug 2009
    Location
    Sterling, VA
    My Bikes
    '77 Fuji S-10S, '82 Fuji Team, '88 Fuji Saratoga, '08 Scattante CFR, '12 Jamis Sputnik, '13 Motobecane Fantom29 HT
    Posts
    2,395
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That. Or electromagnetic interference. Sheesh - I don't even like indexed shifting that much.

  22. #22
    Junior Member
    Join Date
    May 2012
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Ok, I always push off with my right foot, remaining clipped in on the left. I think the FD actually moves very slightly but now I want to double check it. I do know that I am nowhere near the shift buttons, so it is not an accidental shift.
    Last edited by nrgy; 05-17-12 at 06:07 PM. Reason: mispelling

  23. #23
    Senior Member
    Join Date
    Sep 2004
    Location
    boston, ma
    Posts
    2,841
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    the fd auto trims depending on where you are in the back and front chainrings. im guessing the fd trims too much due to a sloppy limit screw adjustment. also check that the support screw is mounted properly.
    Last edited by reptilezs; 05-17-12 at 07:06 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •