Garmin hrm pro not connecting via BT protocol

My garmin hrm pro is no longer transmitting to zwift via bluetooth protocol. Connected ant plis dongle and the unit works. Is this a known bug since recent updates ?

Do you use it with any other apps or devices? Try force closing any apps you have used it with or turning off other devices and see if that clears it up.

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ANT+ sensors will broadcast to multiple receiving devices. BLE is limited to one device per channel. This thread will have some insights:

I was the dummy in that thread. Don’t be like me.

Not quite - Garmin HRM Pro’s can connect up to 3 BLE devices simultaneously.

I stand corrected! They now support 3 BLE connections.

Minor correction: the HRM-Pro supports two simultaneous Bluetooth channels (so two BLE devices there) and additionally has an ANT+ radio which supports virtually unlimited receiving devices. (per DCR)

My suspicion is OP has “something” attempting to steal one or both of the BLE connections.

More clues in the linked thread but an example would be Garmin Connect attempting to maintain a background connection to the HRM-Pro taking up one of those channels, as well as something like a smart watch or bike computer taking the other. Zwift can’t “see” the HRM-Pro because the other devices are being “greedy”, even if apparently closed - many run in the background silently.

It is 3 BT connections alone so you could be right but that’d be 3 things connecting to the HRM before Zwift gets a chance.

Unlucky but as you’re experience shows it’s possible.

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Have to say, I bought our one for my biking needs (I have a few old ANT+ only) and since I have very little tolerance for faffing about with things not pairing, my daughter now has the Pro (and I’m happy with my ANT+). I get networks and radio type stuff but BLE/BT can be bloody weird.

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Don’t fix what’s not broken. I use a HRM2 with ANT+.

No connection issues and only a flat battery to give me any concern every couple of years.


haha, so right. A little while ago I decided to convert everything I could to BLE in my biking world because, well, why not! Silly as I have never had issues with ANT+ either.

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Well I’ll be…the HRM-Pro and Pro+ (same guts, different shell)… do indeed support 3 BLE connections now! Not sure if that was a launch feature or part of the firmware update after the HRM-Pro+ launch.

I’m right with you on ANT+. I heavily favour it over BLE for sports fitness connectivity. ANT+ seems to be more fault-tolerant, picking up where it left off in the case of a signal drop. When BLE fails, it fails hard.

@James_Foale : one more thing to do is check your HRM Pro for firmware updates using Garmin Connect.

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Seems like i have some more investigating to do on hidden connections. Have ruoes out it being an issue with the device itself. So will work through finding the hidden spy in my camp on BT and go through firmware updates. Pretty sure indknt have 3 linked devices but never know.

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