Garmin HRM-DUAL Specifications + Opinion

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Garmin today announced their new heart rate monitor: HRM-DUAL

It’s a more connectable, updated version of the old HRM3-RUN model and probably marks the start of new refreshes to many of Garmin accessories as we predicted way back in last year.

Why this HRM? Why Now?

Garmin’s HRMs are great. As are those of Garmin’s competitors (Wahoo, Polar and Suunto). The one thing that was lacking from the whole of Garmin’s HRM offerings prior to today was Bluetooth BROADCAST Connectivity. And it’s been notably missing for over a year.

Again you say “Why?”. Surely, after all, Garmin are Captains of ANT+ World? Why BLE?

Indeed so. But the world is moving on and it’s all Zwift’s fault…in a nice way.


The HRM-DUAL (Specifications, below) looks to be EXACTLY the same format as the old HRM3 format. Even the strap looks identical – which is cool. It was my favourite-looking strap of all-time. I have ‘a thing’ for heart rate straps and pods;-)

Yes, the specifications are unchanged – in terms of the battery type and dimensions. Yet the expected usage time based on one battery has fallen by about a third. I would assume this is because of the extra requirements of dual BLE-ANT+ transmission. Because battery life has fallen I don’t expect there to be too many, if any, changes to the electronic innards. It would have been nice to see an electronically more efficient unit, I suppose.

The HRM-DUAL’s specifications show that it is not sufficiently waterproof to take into a pool but, then again, there’s no point as it will NOT cache HRM underwater like the HRM-TRI and HRM-SWIM. The only issue here will be those wearing it under a tri-suit and then hoping it will work for the bike and run leg of a triathlon…you might be OK doing that.

So, the elephant in the room is the dual-BLE+ANT+ transmission.

*Two* BLE channels are broadcast simultaneously alongside the ANT+ channel. That means you can have Zwift-RUN supplied with HR data as well as a Polar Vantage V, as well as a million Garmin ANT+ devices. All fed by the one HRM-DUAL.

  • Of course, the main target market is Garmin users who have previously had to buy an ANT+ dongle to plug into their computer for Zwift to translate the ANT+ signal so that Zwift can use it. No longer !! That dongle is not now required.
  • The other target market is someone like me who needs to potentially pair to several devices simultaneously from different manufacturers (a small market admittedly!)
  • Then sometimes, just sometimes, it’s actually handy to be able to pair by BLE (even to a more recent Garmin device) as you know you might otherwise be picking up another signal from the worng sensor. BLE devices nearly always appear as ready-to-pair with a proper name visible.
  • Finally, a notable number of people use waking HRV apps to feed into their readiness numbers. You always had to have an extra strap to do that…not now.

I have a slight preference for Garmin’s HRMs compared to Wahoo (although I love Wahoo’s other products). Sure there is a slight price premium, the price is $70 on I may well get one of these as I am using a 4iiii Viiiiva at the moment which performs a similar, dual-band task (one BLE channel but also cleverer bridging functionality). Although I just know that Garmin’s next HRMs are going to be even more exciting, so I may wait even though the Viiiiva is eating batteries like cake.


Yep, it’s going to be accurate. Let’s move on…

Nothing to see here.



This is only the start.

Expect to see the HRM-TRI/RUN/SWIM models similarly updated with two BLE channels. Remember, they cache data as well which is what you need if you don’t want to carry your recording device and/or you are swimming (tri).

I suspect we shall also see optical ARMBANDS like those offered by Wahoo (TICKR-FIT), Scosche, Runar and Polar (OH1). Again with dual-BLE but clearly based on the Garmin ELEVATE oHR sensor unit. I would say this is highly likely to happen as there are a lot of people who don’t like wearing chest straps and a lot of people who have come to realise that wrist-based oHR has no guarantees of accuracy. An upper-arm band solves those two problems. Imagine if it could cache data too and have a battery life of over 30 hours. Cool.

Also, don’t forget, that as much as you or I might like ANT+, it is BLE that is probably the way of the future. But that will be a few more years yet before that statement becomes more widely accepted to be true.

Garmin HRM-DUAL Specifications

Exactly the same as the “Soft strap premium HRM” except where shown in bold

  • Module: 2.4″ W x 1.3″ H x 0.4″ D (62 mm x 34 mm x 11 mm)
  • Strap Length: Adjustable from 25″ to 52″ (63.5 cm to 132 cm)
  • Weight: 1.9 oz (54.4 g) [old model was 1.6 oz (45g) ]
  • Water Resistance: 1 ATM
  • Battery: User-replaceable size CR2032 (3 volts)
  • Battery Life: Up to 3.5 years (based on average use of 1 hour per day) [old model was 4.5 years on the same basis, although this battery life is superior to HRM-TRI/RUN/SWIM]
  • Operating Temperature: 23°F–122°F (-5°C–50°C)
  • Radio Frequency/Protocol: 2.4 GHz ANT wireless communications protocol; BLUETOOTH® Wireless Technology 5.0
  • Range: 3 m
  • System Compatibility: ANT+, BLUETOOTH (dcrainmaker confirms dual-simultaneous BLE connectivity)
  • Data Transmitted – Just HR and RR (HRV) no fancy running metrics
  • Caching? – No
  • Firmware updatable via your Garmin smartwatch (certainly the high-end ones)

Compatibility: The ANT+ side of things will work with any Garmin although as we’ve said there is no caching. In terms of the Garmin devices that support BLE then I’m pretty sure that nearly all of you will know if your device can support that already. Basically, it’s the high-end devices that also support BLE eg Fenix 5/935 and others. The BLE channel should be compatible with every Polar, Suunto and Wahoo device that supports BLE and also compatible with any iOS and Android sports app – although you will probably find getting it to pair on an old version of Android potentially difficult…but that’s won’t be Garmin’s fault.




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I would be amazed if garmin didnt push out an optical sensor that could be worn on the arm – like a Rhythm and TICKR FIT.
DCR suggested in the early days that the FIT may be expanded to do caching etc – thats not happened. The Rhythm 24 seems to still be struggling and not working as promised – with hardware issue thrown in for good measure.
The market is ripe for Garmin to jump in with a dual band optical sensor that can cache data. They have the components – they ‘just’ need to repackage. As they control their end to end manufacturing process, that shouldnt be too hard.


Too little too late ? Probably not but that format is so 2013 😉 They should have released a dual HRM-RUN/TRI/SWIM directly. The HRM-RUN is by far the most reliable HR device I’ve ever had and I’ve had a good dozen. It’s only failed me once during an interval session in the heat.

Marathon Man

Good to see this can actually do dual bluetooth channels as well as ANT+. Useful for us Vantage / Humon owners that also use an Edge cycling computer…. 🙂


How does multi transmission work for you? If i run with my SST and FR630/645 my rhythm+/24 lags like crazy, The stryd does worse, pace diminishes to zero. It appears to me, that while they maybe dual standard. Both standards cannot be used at the same time.


Which is the best HRM? Garmin dual, Garmin run, myzone MZ3 or tickr X?

I have a garmin watch …does that makes any difference? Or would the tickr X be just the same in terms of connectivity etc?


Accurate, compatible/connectivity with garmin watch, easy to analyse data in one place ability to analyse cadence etc.

In simple terms, what would you buy if you didnt have one right now and wanted to connect to a garmin watch as well as an iphone and a bike computer.


Does it provide HRV R-R intervals?
I didnt get this information nowhere.


Do you know the accuracy of R-R intervals.
I wanna buy a product that communicate with HRM via bluetooth but it has to measure R-R intervals with an accuracy to one thousandth.