Power2Max / Garmin HRM signal dropping constantly.

(Hanjong Ko) #1

I thought it was the actual signal being weak, so I’ve tried TrainerRoad and it’s working perfectly in TR.  I am getting no signal in Zwift.  It was working fine before the latest update, I think.


Any idea?

(Eric Min) #2

Are you using a USB extension cable for the ANT+ dongle? 

(Hanjong Ko) #3

No, I’ve tried using 5-meter USB 2.0 extension cable but that made no difference.  

(Hanjong Ko) #4

If it were a hardware issue (weak signal), I should be having the same problem in TR as well, don’t you think? 

(Eric Min) #5

Just to confirm, you are not using a Garmin head unit to relay to TR?

Also, just want to confirm that Zwift is having a difficult time reading your HRM. 

Finally, which ANT+ dongle are you using?

(Hanjong Ko) #6

I am using a generic one bought here in Korea.  Do you think it’s the dongle?  




(Eric Min) #7

It should be OK but you should ask the other Korean users if they are having similar issues with it. 

Is your power meter and heart monitor also using BLTE? Do you have an iphone? Because then you can use our BLTE connection via the mobile phone which will then connect to the game via WIFI. 

(Hanjong Ko) #8

Power2Max and my HRM only supports ANT+ as far as I know.  Also, before the latest update (a few days ago I think), it was working fine.  After the update, it was getting no signal.  And another software works fine, so I am assuming it’s the software not the hardware.

(Eric Min) #9

Are you also running the Garmin software? If so, can you try uninstalling it? 

(Chase Culpon) #10

I’m having a similar issue–I have multiple garmin HRM that used to work perfectly but have stopped coming up at all starting this week. Same ANT+ USB dongle is handling other devices fine with ZWIFT. Will reply with more once I’ve had time to troubleshoot more thoroughly…

(Hanjong Ko) #11

I’ve now solved this issue by getting a different 3-meter USB extension cable.  I believe 5-meter cable was out of specification.  It’s not working great.



(Chris B (D)) #12


I seem to have a similar issue.

I logged 11 hours on Zwift beta with no issues with my setup, then had a break until this week. Now my speed/cadence sensor and HRM strap keep dropping out. It is incredibly annoying, especially as I planned to do my first 100k ride on the weekend.

Here’s what I’ve trouble shooted so far:

  1. Not batteries in the sensors, as both drop in and out. There is no way two different sensors I’ve owned for greatly different lengths of time are flat at the same point.

  2. Not hardware, as nothing has changed there

  3. Software did a huge update when i rode for the first time in two or three months on the weekend. This seems the most likely to me.

  4. I do have the Garmin software running in the background, but will remove it before I try again.

  5. First ride back, over an hour, all the issues were in the first five minutes. Tonight I gave up when it happened again and didn’t push through to see if it correct itself. 

So, Zwift, what do you suggest? 

(Garmin ANT+ speed/cadence, Wahoo BTLE+ANT+ HRM strap, Suunto ANT+ dongle with and without a 3m extension cable, computer is MacBook Pro, early 2011)

(Chris B (D)) #13

Meant to ask, how do I get this to work

''Is your power meter and heart monitor also using BLTE? Do you have an iphone? Because then you can use our BLTE connection via the mobile phone which will then connect to the game via WIFI. ‘’

So I can have my BTLE HRM and a BTLE speed/cadence talk to the iPhone Zwift app and then it’ll relay them to the computer? That would make my life much easier if it works. No 3m USB extension cable!!