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Thread: Ultegra Di2: Is this a symptom of "crash mode"?

  1. #1
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    Default Ultegra Di2: Is this a symptom of "crash mode"?

    Mystifying problem that's happened several times to my wife's 2018 Ultegra Di2-equipped bike: After some seemingly innocuous contact between the RD cage and a solid object while the bike is stationary, when she then picks up her bike and starts to pedal it instantly upshifts into the smallest cog, and will not shift back up the cassette to any larger cogs.

    This regardless of what cog or chainring she was in when she parked the bike.

    This most recent time it happened when she parked it next to a curb with the drive side facing into the curb, and either A) inadvertently leaned the rear derailleur cage against that curb, or B) brushed her calf against the RD as she was mounting the bike. A couple times in the past it happened when she parked the bike in one of those bike racks that cradle the rear wheel; same deal though, the RD cage made contact (got pushed against the bike rack) while the bike was not being pedaled.

    In all cases, the chain goes down to the smallest cog and can not be coaxed to shift out of that cog.

    The first time it happened and I was around I fidgeted with the RD, manually pushing it in towards the larger cogs while randomly hitting the upshift button on the right lever...eventually it miraculously-though-inexplicably righted itself.

    On yesterday's ride, it happened yet again and no amount of fidgeting seemed to fix it. So she rode the last 10 miles in her small/small combination (thread drift: my wife is a badass) to the nearest bike shop. The mechanic there took it downstairs, and ~3 minutes later brought it back and said "You're all set."

    I asked "What did you do to fix it?" and he essentially replied "I fidgeted with the RD, manually pushing it in towards the larger cogs while randomly hitting the upshift button on the right lever"

    :::facepalm:::

    Okay, so that's really not a satisfactory answer for me...nor is that a reliable/repeatable solution should this ever happen again, especially if she's more that 10 miles from the nearest bike shop.

    Anybody have an explanation for what exactly could be going on here, and what a more process-oriented (and Shimano factory-sanctioned) cure is?

    A couple of internet whizzes have suggested that the Di2 system had gone into "crash mode" and they offered the proscribed button-press to get out of "crash mode". That's great if this is indeed what's happening...but is Ultegra Di2 so sensetive that a minor brush with one's leg against the derailleur, or leaning the RD cage against a curb, is enough to engage it? Is it really that easy to cause it to go into "crash mode"?!?! Or is something else entirely going on with her bike?

    Any suggestions greatly appreciated. Thanks.

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    Default Re: Ultegra Di2: Is this a symptom of "crash mode"?

    Sounds like crash protect mode but also sounds over-sensitive. Could be that earlier in a not so gentle moment something got damaged, like the cable, or partially detached, like the cable, and somehow that’s what is triggering the response. Give it a good looking over and see if anything is loose. Then put it on the work stand and give it a couple whacks with a flyswatter or something equally light-handed and see if you can duplicate the reaction. If it goes into protect mode, do the recovery sequence and see if it comes back.

    My wife has knocked over her bike a couple times on the derailleur side, and it hasn’t gone into crash protection mode. I was a little surprised.

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    Default Re: Ultegra Di2: Is this a symptom of "crash mode"?

    Quote Originally Posted by Bob Ross View Post
    ...but is Ultegra Di2 so sensetive that a minor brush with one's leg against the derailleur, or leaning the RD cage against a curb, is enough to engage it? Is it really that easy to cause it to go into "crash mode"?!?! Or is something else entirely going on with her bike?
    It should not be that sensitive.. I have hit my older 6870 rear derailleur with various objects to try and force it into crash mode.. but no luck. It should never really go into crash protect mode on its own (or when pushed against a bike rack).

    However.. it does sound like it's going into crash protect mode. Like j44ke said, put it in the work stand and give it a couple whacks (just don't use a hammer or screw driver like I did..) and see what happens.

    If it goes into crash mode that easily I would ask the LBS to contact Shimano to see if they'd replace it for free. Sure, it's out of warranty since it's more than two years old, but Shimano sometimes replace these anyway.
    Any LBS should be able to contact Shimano, even if you haven't bought the bike there.
    BetterShifting.com - Di2 help and guides

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    Default Re: Ultegra Di2: Is this a symptom of "crash mode"?

    Your post about leaning bike against the curb made me think of this quite invaluable invention from bikebrake.com...it's a bike emergency brake. I can't tell you how many times I have seen bikes leaned against a wall or a curb topple over to hit the pavement. If you use one of these or something similar it's much more likely your bike will stay planted where you set it. Way lighter than a kickstand :).

    https://bikebrake.com/

    Or another approach from the maker of Click-Stands: scroll down to the bottom for "brake bands."

    http://www.click-stand.com/products-and-ordering.html

    Or cut a cross section from an old inner tube.

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