4iiii Viiiiva Heart Rate Monitor, ANT+ to Bluetooth Smart Bridge Review – Zwift Gear Tests

The number of heart rate monitors on the market is mind-boggling. Most sports gadgets come with an HRM in the box, or at least the option. I personally have 5 knocking around the house – so why buy a separate HRM? Extra features!! With the 4iiii Viiiiva Heart Rate Monitor working as an ANT+ to Bluetooth bridge, this is  likely to be a very useful heart rate monitor when it comes to using the new iOS Zwift platform!

4iiii Viiiiva Heart Rate Monitor, ANT+ to Bluetooth Smart Bridge Review – Zwift Gear Tests

4iiii Viiiiva Heart Rate Monitor

With the launch of Zwift iOS beta, the ability for cycling sensors to broadcast on dual ANT+/ BlueTooth channels suddenly became a lot more important. Previously it was people with the likes of Polar’s HRM’s who were left out in the cold as Garmin Vector riders laughed their ANT+ puritanical laugh whilst connecting to Zwift computers via their dongles. The Zwift Companion app has helped with some Bluetooth sensor issues, however, the shoe is now on the other foot, with BlueTooth sensors being the only way to get riding on Zwift iOS. ANT+ only kit is looking a little glum

So what is the rider with a stack of ANT+ only devices going to do?

Mio released the optical HRM monitor, the Mio Velo in 2014 which acted as a bridge for ANT+ speed and cadence sensors, taking the signal, and re-broadcasting it over BlueTooth. However, the update to allow for ANT+ power broadcasting never materialised 🙁

4iiii Viiiiva Heart Rate Monitor

So if you have a power meter broadcasting purely over ANT+, like the Garmin Vectors, what option is there? Apart from buying a new power meter, which isn’t an option for most people!

Kip Fyfe, one of the original ANT+ inventors, and importantly CEO of 4iiii is able to build bridges, literally, between the warring ANT+ and BlueTooth smart camps, with the 4iiii Viiiiva Heart Rate Monitor. Released in 2013, the Viiiiva is able to bridge ANT+ signals, including power, and rebroadcast to a BlueTooth only device, such as iOS, thus allowing your Garmin Vectors or other ANT+ power meter to work with Zwift iOS. Or with any other app on your BlueTooth smartphone for that matter, such as Strava, or MapMyFittness.

Device Design

4iiii Viiiiva Heart Rate Monitor

As we’re talking about an HRM, there is very little in the box, we have a chest strap – with the connections at the front, a quick start manual, and the 4iiii Viiiiva Heart Rate Monitor itself.

Not really much to see on the front of the device…

4iiii Viiiiva Heart Rate Monitor

On the back, we have the RIGHT/LEFT strap connectors, ANT+ and Bluetooth Smart logos, as well as Liiiink identifications. Plus the battery door for the CR2032 user-replaceable battery.

4iiii Viiiiva Heart Rate Monitor

Compared to other HRM’s on the market, the 4iiii Viiiiva Heart Rate Monitor is on the slimmer side of things, with tapered edges only adding to this effect

4iiii Viiiiva Heart Rate Monitor

Note you are going to be able to connect to Zwift iOS with both the Polar and Stryd HRM above, but they lack the bridging function of the 4iiii Viiiiva Heart Rate Monitor to connect other ANT+ sensors

4iiii Viiiiva Heart Rate Monitor

As mentioned, the strap with the 4iiii Viiiiva Heart Rate Monitor is an end connection strap, unlike the offerings from Polar and Garmin:

4iiii Viiiiva Heart Rate Monitor

If you have spare Garmin straps hanging around though, the 4iiii Viiiiva Heart Rate Monitor will attach there nicely too

4iiii Viiiiva Heart Rate Monitor

Although, because of the raised rubber on Polar straps, you are not going to be able to connect there:

4iiii Viiiiva Heart Rate Monitor

That’s it really, externally, a simply HRM, nothing more to see.

Specifications

  • Battery life: about 200 hours
  • Battery: CR2032
  • Communications: ANT+, BlueTooth Smart
  • Weight: 5 g (1.76 oz)
  • Dimensions: 6.5 cm x 4.5 cm (2.55 in. x 1.77 in.)
  • Operating temperature: 0–50 C (32–122 F)
  • Waterproof rating: IP 67
  • Activity logging: 65hrs onboard activity storage
  • Accuracy: R-R variable tracking

The 4iiii Viiiiva Heart Rate Monitor manual can be found here

Using the Device 

As well as using all the fancy functions of the 4iiii Viiiiva Heart Rate Monitor, you can also just strap things on without any setup, connect to your devices and head out for a run or cycle – as the technology of the 4iiii Viiiiva Heart Rate Monitor is established, when I tested a couple of sensors together, they all showed exactly the same reading with a beat or two

4iiii Viiiiva Heart Rate Monitor

So strapping things straight on gives us simple HR data. To go any further into using the Viiiiva’s functions you need to download the 4iiii app

4iiii Viiiiva Heart Rate Monitor

Zwift Gear Test

The iOS app for the Viiiiva is here – and is required to access the bridging functionality with Zwift iOS

4iiii Viiiiva Heart Rate Monitor
Inside, you pair your Viiiiva, either through the  Viiiiva Configuration menu, where you can either scan, or, assuming you have firmware 2.0, connect by tapping the HRM to your iOS device

4iiii Viiiiva Heart Rate Monitor

Once you are connected to your phone you can scan to connect to your ANT+ devices to the 4iiii Viiiiva Heart Rate Monitor

4iiii Viiiiva Heart Rate Monitor

Crucially the 4iiii Viiiiva Heart Rate Monitor allows devices to connect through it, so you are not going to be breaking any established connections to Garmin GPS units for example whilst using the Viiiiva whilst on Zwift iOS

You may have noticed in the above picture the Viiiiva ID  is coming’s up as “JAG’s 4i”. You can change the BlueTooth ID tag to whatever you would like which makes multiple Zwift setups a little easier

4iiii Viiiiva Heart Rate Monitor

Once connected to your devices you can review your ANT+ list easily, in case you need to swap a sensor

4iiii Viiiiva Heart Rate Monitor

You can then move over to the activity side of the 4iiii app to ensure that things are working, as well as connected, before moving on to connect to Zwift iOS – It should also be noted that you can trigger a calibration request from your power meter from the 4iiii app at this point before the start of your race/ride

4iiii Viiiiva Heart Rate Monitor

It is worth while checking you can see the data streams in the app before you move on, as the 4iiii Viiiiva Heart Rate Monitor seems to only want to connect to ONE BlueTooth receiver at a time. So in order to connect to Zwift iOS, I had to shut down the 4iiii app, briefly kill the BlueTooth on my phone. Only then after a couple of seconds was I able to scan and find the 4iiii Viiiiva Heart Rate Monitor in the various Zwift iOS sensor fields on the iPad.

Initially, when starting off this review, I couldn’t seen any of the ANT+ sensors on Zwift iOS I had connected to the Viiiiva, which I now know was due to having the 4iiii app connected to the Viiiiva

4iiii Viiiiva Heart Rate Monitor

There should be no issues running the one BlueTooth physical sensor on many different sensor channels, as Zwift is able to decode the layered data streams without issue. Some other apps, although not many now, don’t play as well, and instead require a rotating the data stream the Viiiiva sensor sends out, which isn’t great for a power meter, due to the drop outs, when the other data is being sent! It should also be noted that you can trigger a calibration request from your power meter from the 4iiii app before the start of your race.

Interestingly enough, given that the 4iiii Viiiiva Heart Rate Monitor has an onboard memory, if you happen to have a head unit failure – occasionally I do forget to recharge a Garmin – the Viiiiva will continue to record the session with any connected sensors, so you can still paw over your Zwifting data to see what areas you need to improve in order to win your KISS podium place.

4iiii Viiiiva Heart Rate Monitor

Conclusion

4iiii Viiiiva Heart Rate Monitor

At £79.99 from 4iiiii directly, the 4iiii Viiiiva Heart Rate Monitor is around the same price as other smart HRM offerings from the likes of Wahoo, whose Tickr X is a similarly useful bit of kit (I STILL love the tap to change track functions), BUT crucially lack the Viiiiva’s ANT+/BlueTooth bridge functionality when it comes to Zwift and iOS.

4iiii is very proud of their desire to keep updating the firmware of the Viiiiva, giving increased functionality to an existing product, so you never know, I might one day, get my “tap to skip functionality”, I can always hope. Particularly as this would really elevate the Viiiiva for me, moving beyond bridging ANT+ sensors like the vectors for Zwift iOS, onto the top slot as my go to HRM!

If you are a largely Garmin, or at least an ANT+ household, when it comes to cycling sensors, getting on Zwift iOS might prove initially to be a costly upgrade if you wanted to move over to sensors with a dual channel setup – the 4iiii Viiiiva Heart Rate Monitor resolves that issue nicely, in a cost effective package.

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  • John

    I purchased a Viiiiva HRM/bridge a couple of days ago and on reading the comments from Lee I removed the rear battery cover and applied some silicon grease to the seal which will help keep moisture out on the battery compartment.
    I applied the silicon with a very fine artist paintbrush to ensure no excess silicon was a put near the battery terminals.

    Do not be tempted to apply the grease with your finger as an excess of grease will cause a short circuit if it were to come into contact with the battery contacts.

    Silicon grease is an ideal barrier to help prevent water ingress around the seal and is used in harsh marine environments to keep water out of electrical equipment.

    Hope this helps others

    • I’ve done the same on the powertap C1 chain ring battery housing because of sweat

  • Bruce

    Hi,

    Is the bridge also able to send ANT FE-C data? Can resistance still be controlled?

    Thanks.

  • Lee

    Nice review – as a long term user of the product, I’d point out that there is some fault with the battery cover, my first met its demise because of water ingress and my second is on the way…….

    • Interesting point. Not seen any issues with sweat, but will keep an eye on in.

      • Lee

        And another one bites the dust ! not sure if you can see the corrosion on the battery and inside the unit.

        Training indoors kills them, I assume because lack of cooling/evaporation the water (sweat) effect is amplified……

        • I’ve seen a few pics of aluminium bikes corroding around the bottle mounts too. Zwift is properly hard work!

          It’s a shame MIO didn’t finish the firmware on the Velo, as a sealed optical HR device would be great!