Unfortunately, I have one of the failing 4iiii powermeters, which suddenly starts massively misreading the watts (over-reading) and is unable to calibrate. I have been in contact with 4iii, who sent me the instruction here: https://docs.google.com/document/d/1elLsrGRZ4P_SjmzXphXSytmUv4VKTv2jeye-riXkGUA/mobilebasic. Unfortunately, it did not fix the problem. Since there is no warranty left, I am really left with a problem here. It has only been used on my summer bike and not a whole lot.

So, I would really love to hear, if anyone knows of a fix to this problem, which seems to be so common that it comes close to being a class failure.



  • Have you replaced both batteries? (If you did, remove and wait a minute before putting back in.) Is the firmware up to date? Unpairing and re-pairing may help I had similar trouble with Powertap pedals where waiting to put in the batteries seemed to do some kind of reset.
    – Carel
    Commented Jun 11, 2020 at 11:48
  • Thanks. Yew. New battery - there is only one - latest firmware. I would really love to hear from anyone who has been able to fix this issue. Morten
    – Jensen
    Commented Jun 11, 2020 at 18:23
  • do you happen to have a copy of this Google doc? The link does not work any longer. Commented Jul 8 at 21:55
  • @MaxTheisen does 4iiii.com/wp-content/uploads/2014/09/… on page 4 help your situation?
    – Criggie
    Commented Jul 9 at 2:22
  • @MaxTheisen and to the original poster - we had a related discussion a while after the question was asked. the solution is a bit involved, but perhaps it will help?
    – Weiwen Ng
    Commented Jul 9 at 10:14


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