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Cycling Gear Reviews

Garmin 920XT Cycling – Triathlon Watch Review – TitaniumGeek

Garmin is known for their GPS units, and cycling head units. With regard to being a triathlon watch, is using the Garmin 920XT cycling function as effective as the running metrics? Does it bring anything new to the table, or is it a stretch too far for this already feature filled watch?

Garmin 920XT Cycling Watch Review

The Garmin 920XT is not a simple device. In order to do the watch justice, and to explain the myriad of features, this review has been split into several different posts:

Given my bike injury prior to purchasing this watch, the Garmin 920XT cycling functions have largely remained untested until recently when my arm has finally improved in strength enough to support the bike for longer than 30mins! Finally in Scotland I was able to build up to over an hour in the saddle. In addition to enjoying some create tarmac and views its allowed me to review the Garmin 920xt cycling features, and compare them with the Garmin 1000 head unit – review coming later!

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Nice smooth roads!

Connections Galore – or not!

The Garmin 920XT cycling mode can work just as well as your normal cycling head unit, except with a potentially smaller screen.

The 920XT allows connections to just about any ANT+ sensor, it seems that Garmin is dead set on refusing to incorporate bluetooth LE sensors. Which is a shame, although at the same time understandable as Garmin owns the ANT+ protocol, and thus has a vested interest in its promotion.

Being the ANT+ capital of the world however, if it beams on ANT+ (assuming not a private channel e.g.  Shimano D-Fly Di2 connectivity kit). This means that the majority of bike sensors and power meters will be compatible with the Garmin 920Xt.

Personally I like redundant systems, and, thus quite like dual channel sensors such as the Wahoo Blue SC speed and cadence as it allows me to connect to my phone if needed, but the rest of the time, given the ANT+ broadcast will also work with the Garmin 920xt, or any other ANT+ garmin device.

The broad range of ANT+ support will be a particularly useful facet when it comes to testing the Styrd running power meter – which should be arriving in JULY 😊, as I will be using the Garmin 920xt with the new running power meter, but as there is no support from Garmin yet – I’m hoping for an IQ app on the watch, I will have to use the cycling mode on the 920XT in order to access the power data function when I’m out running. However as I’ll still be getting speed data from the GPS chipset inside the watch, I shouldn’t have any problems, although I’ll miss my pace data!

Physical Connections

If you like your triathlon watch constantly front and centre, a Garmin quick release kit is available. This requires the fixing of a backplate to the watch, which in return allows you to quickly detach the 920XT from your wrist, and place it on a normal Garmin quarter turn mount. This could either be your own mount, or the small plastic bike mount included with the kit – seen in the centre bottom of the picture

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Garmin Quick release kit

Initially I didnt think this was going to be particularly useful – especially as it increases the height of the watch ever so slightly on your wrist due to the backing plate, and that my intention, when I get back to doing triathlons, is to have a Garmin head unit displaying data on the bike AND the 920XT monitoring the whole event. But some people prefer to pair weight down to an absolute minimum, so its nice that the option is there for people who want to use a single device throughout. Although given the price of the Garmin 920XT, its a bit of a shame the quick release kit isn’t included in one of the watch bundles.

Indoor, Outdoor

On the Garmin 920xt cycling can be done on two modes – indoors and outdoors

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Outdoor cycling mode

In each case the icons along the top left of the screen inform you that your sensors are connected and working, prior to initiating the ride.

Data Fields

On the image above, working LEFT to RIGHT, that is:

  • GPS signal – full
  • bluetooth phone connection – connected
  • Heart Rate – connected
  • Speed sensors – paired, no connection
  • Cadence – paired, no connection
  • Power meter – paired, no connection
    • There is also an icon for the VIRB camera, but this was not attached to the 920xt at this stage

The important that you select the indoor cycling, when doing just that

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indoor cycling mode

Indoor cycling allows  you to track speed and distance from speed and cadence sources, such as a trainer like the KICKR, or from a simple ANT+ speed/cadence sensors, rather than the GPS, which will place you going nowhere

It genuinely took me a while to figure this out when using ZWIFT, as to why I was getting Strava maps which just buzzed around the house, getting no distance data on the watch, in spite of me being connected to the KICKR and seeing speed data on the from the watch, and distances on Zwift.

Simply ensuring that I was cycling using the indoor, not outdoor cycling modes stops the Garmin 920XT pulling distance data from the GPS chip set, and instead priorities and calculates speed, and thus distance from the external sensors! – Yes fool  I know!

Cycling Metrics

As with the running section of the watch, the Garmin 920xt is able to calculate your cycling VO2 Max. This is the first device from Garmin which has had this function built in, and currently I remain surprised that it hasn’t been extended to the Edge family of devices in one of their frequent updates.

That said, given how flaky the Garmin 1000 can be with regard to bluetooth connections I do wonder if Garmin has devices produced in hermetically sealed teams, which dont trade ideas and solutions!

The Garmin 920XT covers a multitude of cycling metrics, which can be displayed in different screen variations across 4 data screens each showing between 1 and 4 data fields, in addition to map, virtual partner and clock.

Personally with the size of the screen, I found anything small than two display fields too small to reliably check on the move. But the smaller fields are good to have for when paused, or checking your ride. But not what I’d term glancible – well not with my current bike handling skills anyway!

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Biking with the 920XT

All of the series of usual fields are present

  • Timer fields
  • Distance fields
  • Speed Fields
  • Heart Rate fields
  • Cadence fields
  • Power fields
  • Elevation fields
  • Other Fields
    • Calories
    • heading
    • laps
    • sunrise
    • sunset
    • Time of day – Useful on a watch!
  • Gear fields – if you have Di2 Gears and a Shimano D-Fly

Cycling VO2 Max

Why do I need a separate VO2 max for cycling and running? Isn’t it all about oxygen utilisation?? I’m still using the same lungs and muscles am I not? How do these differ?

Well for starters there is the way that the two numbers are calculated, and hence why I have different readings for both

You need sport specific VO2 Max data as an indication of training, and ability. Simple because whilst it is the same you, you are working in a different capacity. Perhaps the best way this can be seen is through breathing. When running, the physical action of pumping your arms helps you to move the chest wall, forcing air out. You dont get this when cycling, and the pressures on the differing muscles of your legs are different. Hence the need to identify your cycling vs running VO2 Max

The cycling VO2 Max needs a power meter in order to be able to complete the calculation. This might put this functionality out of the reach of a proportion of owners of the watch, which is a shame. Although using a Watt Bike with ANT+ compatibility would allow for personal testing and monitoring of improvements if you dont have a power meter.

Like the VO2 Max for running, I found a degree of drift using the Garmin 920xt, simply because calculating a VO2 max takes time to accurately determine your numbers. Personally I found a continual increase over the first 5ish cycles as my distances increased, which then stabilised to a pleasing 61.

I initially calculated, and refined mine using the Wahoo KICKR on ZWIFT before actually buying the Stages power meter. Its great to be able to show an increase, not only in strength, but in the actual fitness of your body, if that makes sense

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Cycling VO2 Max

VO2 max and training…

All of these numbers really need to mean something. In the case of VO2 max, this is related to how much oxygen can be used by the body to sustain a maximal output of power. So the higher the number, the more efficient you are. Crucially this doesn’t mean the more powerful you are. This is really highlighted with myself. I do NOT have particularly powerful legs, with an FTP of around 275 watts. I know I’ve certainly never cranked out greater than 750 watts at ANY single point yet. BUT i’m quite efficient with my power through training, hence the VO2 score.

The table below indicates, with regard to training what VO2 max means.

FEMALE

Training Status Untrained Trained Elite
Absolute(l/min) < 3.0 3.0- >3.0
Relative  26-42 40-60 55+

MALE

Training Status Untrained Trained Elite
Absolute(l/min) < 3.0 3.5- >4.0
Relative  36-52 50-70 60+

Source: Costill, D.L. and Wilmore, J.H. (1994).Cardiorespiratory Function and Performance. Physiology of Sport and Exercise.Champaign, IL: Human Kinetics.

There is a more in-depth look at VO2 Max on Velocompetitor.com

Signal Strength.

One minor issue I have noted when using the Garmin 920XT cycling is power meter signal drop outs from the the Stages power meter when using the Garmin 920XT on my wrist when and then cycling on the hoods. I had previously experiences connections drop outs with the Stages power meter however, as can be seen in that review, but this was fixed with a new battery door design. My feeling is that this may be an antenna issue with the Garmin 920XT, as I’ve not had problems maintaining a connection to the large Garmin 1000 head unit during the same rides. Oddly there are not issues when the Garmin 920XT is attached to the handle bars. IF you are planning on racing with the 920XT, it might be worth while checking for a similar issue yourself first.

Conversely i’ve had no issues with signal drop outs from ANT+ when using the Garmin 920XT Bike indoor function. Although here I’m mainly using the feed from the Wahoo KICKR which should be able to broadcast a strong single given its plugged into the WALL!!

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Power hungry KICKR

 

Conclusion

The Garmin 920XT is a good cycling watch. But not great, simply due to its size, which can affect reability at speed and possibly some connector issues. Don’t get me wrong, I use it daily, and have it on when cycling, especially for tracking things like VO2 Max which I can’t do any other way as easily. From a triathlete perspective, I’ll do a race with it on, so I have an accurate record of my performance, and be using it actively during the swim and the run. BUT during the cycle section, I’ll keep the 920Xt on my wrist, and use my Garmin head unit to actually give me data on my physical riding during the cycling session, which is big enough I can see it with a glance.

Just in case someone wants to suggest something – NO I dont need my eyes tested, I just like a nice clear/big screen when I’m holding onto the bike and spinning for dear life!

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James Gill

Author of TitaniumGeek, which started after smashing off my RIGHT elbow. Feel free to drop me a line about sports tech, medicine, or frankly anything that you want to chat about!!