"Waking up" eTap

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  • 08-15-2019
    OldChipper
    "Waking up" eTap
    I just installed 11sp eTap on my time trial bike (love it!). However, if the bike is sitting for a while (a few hours), it becomes unresponsive to the shift buttons (the Clics and Blips). I can understand how they would want to preserve battery life by having the derailleurs go to "sleep" after some period of inactivity, but seems like the shift buttons should wake them up. So far either removing/replacing a battery or hitting the shift button *on* the rear derailleur seems to wake things up, but just wondering if this is normal.

    I'm aware of the problem some people have had with their derailleurs going to sleep *during* a ride but that doesn't seem to be this problem and that hasn't happened to me (yet anyway).

    Thanks.
  • 08-15-2019
    cxwrench
    . Generally as soon as the battery senses movement it will wake up. We had the problem where if we didn't remove the batteries from the race bikes in the trailer when driving to races that the batteries would be low on charge even though we had just charged them. SRAM told us to pull the batteries when driving the bikes around. I've never had an etap bike need any more than that.
  • 08-16-2019
    OldChipper
    Interesting, thanks!
  • 08-17-2019
    waltermitty
    I'm still learning but after 12 months of eTapping, I hadn't even notice a wake up tendency yet. Simply pull the bike off the rack and it works. I'll pay closer attention at the beginning of my next ride. So far, it has been great and precise in shifting.

    The only minor glitch (or not) has been at a stop and I'm cross-chained (large crank-large rear). When I try to reverse rotate to re-position so I can pedal off again the chain will drop into next smaller cog in the cluster. So until I figure this out, I just try to quickly blip the shifters before coming to a stop to ensure I'm in 39t ring.
  • 08-17-2019
    cxwrench
    Quote:

    Originally Posted by waltermitty View Post
    I'm still learning but after 12 months of eTapping, I hadn't even notice a wake up tendency yet. Simply pull the bike off the rack and it works. I'll pay closer attention at the beginning of my next ride. So far, it has been great and precise in shifting.

    The only minor glitch (or not) has been at a stop and I'm cross-chained (large crank-large rear). When I try to reverse rotate to re-position so I can pedal off again the chain will drop into next smaller cog in the cluster. So until I figure this out, I just try to quickly blip the shifters before coming to a stop to ensure I'm in 39t ring.

    There is nothing to figure out. You're cross chained...there isn't a derailleur to guide the chain onto the correct cog when you back pedal so it will come off. Nothing you can do about it other than shift before you stop. It will happen with ALL derailleur drivetrains.
  • 08-17-2019
    waltermitty
    sure, I understand. but since this characteristic isn't a given for all 2x11 speed, I'm simply alert to the possibility that it may be a needed adjustment issue on my part. I have a 2x11 DuraAce and Ultegra and neither share this symptom. nothing to lose sleep over but more of a 'hmm'
  • 08-18-2019
    cxwrench
    Quote:

    Originally Posted by waltermitty View Post
    sure, I understand. but since this characteristic isn't a given for all 2x11 speed, I'm simply alert to the possibility that it may be a needed adjustment issue on my part. I have a 2x11 DuraAce and Ultegra and neither share this symptom. nothing to lose sleep over but more of a 'hmm'

    They ( D/A and Ultegra) should do exactly the same thing, unless the cassettes on those bikes are smaller. It will happen more easily w/ larger cassettes.
  • 08-18-2019
    waltermitty
    thanks for the tip. i will dbl check the specs and spacings
  • 09-17-2019
    waltermitty
    Quote:

    Originally Posted by waltermitty View Post
    thanks for the tip. i will dbl check the specs and spacings

    Know your equipment and how to perform adjustments. :-) tuned up the bike mechs per factory recommendations. No more chain rubs or jumps even when cross chained...be it pedaling forward or back.[/QUOTE]
  • 09-18-2019
    cxwrench
    Quote:

    Originally Posted by waltermitty View Post
    Know your equipment and how to perform adjustments. :-) tuned up the bike mechs per factory recommendations. No more chain rubs or jumps even when cross chained...be it pedaling forward or back.



    Adjust a rear derailleur will have ZERO affect on what happens when pedaling backwards. None.
  • 09-18-2019
    202cycle
    Quote:

    Originally Posted by cxwrench View Post
    [/FONT]

    Adjust a rear derailleur will have ZERO affect on what happens when pedaling backwards. None.

    Right? This whole thing is always big talk on the MTB forums. Like it's some kind of defect with SRAM or Shimano this or that. It drives me crazy. Bikes have done this for ages, it's just the way it is.
  • 09-18-2019
    waltermitty
    Quote:

    Originally Posted by cxwrench View Post
    [/FONT]

    Adjust a rear derailleur will have ZERO affect on what happens when pedaling backwards. None.

    uh....that is not what I typed in my reply
  • 09-18-2019
    202cycle
    Quote:

    Originally Posted by waltermitty View Post
    uh....that is not what I typed in my reply

    That's kinda how I read it.
  • 09-18-2019
    cxwrench
    Quote:

    Originally Posted by waltermitty View Post
    uh....that is not what I typed in my reply

    That's exactly what you implied.

    You made adjustments and it stopped happening.
  • 09-18-2019
    waltermitty
    you make this thread sound like a white house twitter rant... knock yourself out. i'm glad I got this resolved for my bike :)
  • 09-18-2019
    duriel
    There was nothing wrong with your bike, ... it was YOU!
  • 09-19-2019
    Jwiffle
    Mine always works without having to be "woken up"
  • 09-21-2019
    aclinjury
    some bikes will not slip the chain when back pedaling while cross chained, while some bikes will slip the chain down the cassette. Like CX said, there is absolutely nothing you can do to fix this except don't do it. The reason why depends on:
    1. angle of chainline (which takes account into chainstay length)
    2. cassette size
    3. the chain itself (Shimano chains will mesh better with shimano cassette than KMC or some other aftermarket ones). I learn this out by swapping KMC and Shimano chain on the exact same bike.

    On one of my road bike which has relatively short chain stays at 400mm, cross chaining (gearing is 52x28) really sucks even pedaling forward, the damn chain grinding sound is loud a/f and I just have to shift that mofo into the small ring. Pedaling backward means instant chain dropping down the cassette. yep.

    on a related note. Back when I was riding a fully suspension (long travel, long wheelbase) mtb bike with 2x9, I NEVER had back pedaling chain drop, NOT once. Now that I'm riding a 1x hardtail (short wheelbase) with a 9-42 cassette (which is bigger than the cassette on the old fully suspension bike which was 34t), the chain will slip down the cassette when i'm in cross chained position, and this can be a little annoying when you're doing a track stand or backpedaling to position your feel for the next up-and-over obstacle.