Di2 Shifting Issue

ibr17xvii
ibr17xvii Posts: 1,065
edited October 2021 in Workshop
Wondered if anyone has come across this before? Essentially as my Di2 battery drains the shifting quality seems to get worse.

I have it on my best bike & when I put it on the trainer for the winter about 10 days ago I noticed that on a shift to an easier gear (up the cassette) the change hesitated slightly but didn't really think much of it. Shifting down the cassette is fine.

As a few rides on Zwift passed I noticed the shifting up the cassette was getting worse & there was quite a noticeable hesitation before shifting up.

Had a play around micro shifting the RD but couldn't get it any better.

So yesterday after fiddling around with it for a while the battery got to around 40% so I thought I'd charge it to see it made any difference & it's back to near perfect.

All the components are new on the bike in April, I got the battery itself in January. Groupset was installed by an ex pro mechanic so I'm pretty sure it's set up right. I've had it hooked up to Etube, all components are recognised, no errors found & all on the latest firmware.

Front shifting is fine no matter what. I haven't tried another battery as they are too expensive to keep a spare of & don't have access to one. It just seems strange to me that it only does it on shifting up the cassette rather than both ways.

Anyone any idea why?

Comments

  • trevor.hall12
    trevor.hall12 Posts: 483
    Has the rear hanger got a knock switching it to the trainer ?
    I would check it first if micro adjust dosnt help .
  • ibr17xvii
    ibr17xvii Posts: 1,065
    trevor.hall12 said:

    Has the rear hanger got a knock switching it to the trainer ?
    I would check it first if micro adjust dosnt help .


    If indexing doesn't work that's usually my 1st thought as well.

    Don't have the alignment tool so can't check but TBH that doesn't really explain why the shifting is fine with a full charge.

    I'm thinking that for whatever reason the battery doesn't have sufficient power to do a upshift when it's not at a decent level of charge but having Googled it no one else seems to have encountered this issue.

    Maybe a battery fault? I can't think of anything else.
  • trevor.hall12
    trevor.hall12 Posts: 483
    If its showing a % of charge and shifting I doubt its the battery
    How is it clamped in the trainer ?
    Since you put it in there something is slowing it or getting in the way
    Assuming you didn't change the shift speed while in e tube
  • ibr17xvii
    ibr17xvii Posts: 1,065
    trevor.hall12 said:

    If its showing a % of charge and shifting I doubt its the battery
    How is it clamped in the trainer ?
    Since you put it in there something is slowing it or getting in the way
    Assuming you didn't change the shift speed while in e tube


    It's just clamped in with a QR on a Kickr. I don't think it's anything to do with that cos I tested it with the wheel back on & it did the same.

    It's not a massive dealbreaker, it just means I'll have to charge it more often.

    I can't get my head around why though.
  • trevor.hall12
    trevor.hall12 Posts: 483
    Only other thing I can suggest is the Bscrew ,I've seen sloppy changes when it needs to push the RD closer to the cassette,though that would be all the time not just when the battery drains.
  • ibr17xvii
    ibr17xvii Posts: 1,065
    At the end of the day the bike still works, I might have to charge it more than I’d like but it’s not ruining my life so it is what it is.

    Still strange, I don’t get it at all.

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