Experimenting with using the Garmin GTU 10 tracker during Ironman Boise 70.3

This past weekend I did a bit of an experiment with the Garmin GTU 10 (GTU = Garmin Tracking Unit), and Ironman Boise 70.3.  Many of you followed along on a separate Twitter account as both The Girl and I raced with the tiny tracker hanging out in our back pockets, tracking our every move.  This is the same tracking unit and supporting technology that was used in the Boston Marathon, as a guest writer wrote about back in April.

So after the race I wanted to loop back around and see what worked and what didn’t work with the setup.  But first, let me show you what the unit looks like, just so we’re all on the same page.  Here it is here, in a picture I took in transition pre-race.


The GTU 10 is a display-less device that only has one button – used to turn it on/off.  The unit is a combination of both GPS and cellular technology to provide continuous updates on the location of the unit, and allow folks to query the status at any time for an immediate update.  The unit can be adjusted to change the update frequency, such that the battery life can accommodate the mission at hand:


In my case, I wanted the most frequent updates, so I set it for 30-second updates – after all, if for some reason it took me longer than 20 hours to finish my half-iron…tracking would probably be the least of my concerns:


The next item was to set up the alerts.  See, unlike your Garmin Forerunner or Edge GPS unit the GTU doesn’t actually create a useful track of where you’ve been (technically it can store some data points, but the data is mostly useless since it can’t understand how you got between those points).  Instead, it’s more of a ‘in the now’ type of device – and simply tells someone where it is at that exact moment.

As such, in order for me to use it to trigger alerts based on my location I had to set up what are known as ‘geofences’.  Geofences are simply little areas of land that you define when you want to be alerted when the unit wanders into, or out of.  You simply set them up on a map by connecting the dots.  It’s just like Paint, except on a Bing Maps instead.


Because I wanted it to alert every 5-10 miles, I drew up a bunch of fences at various points on the course.  Thus, each time I crossed a given fence at a prominent mile marker you’d get an alert.  The Boise 70.3 bike course is mostly an out and back route, which was both good and bad from a geofence standpoint.  It was good because I had to draw half as many geofences, but it was bad in that I couldn’t differentiate whether or not I was crossing mile 15 going outbound…or mile 35 coming back.  Thus, in the alerts, you saw this, which was probably a bit confusing:


Adding to the complexity is the fact that I could only activate 10 geofences per tracking unit.  So this meant I had to ‘conserve’ how many fences I could create.

Here’s what it looked like if I zoomed out a bit to cover the entire course.  The swim is to the lower right, the bike in the center, and the run downtown near the orange dot (me!).  I could have colored the different geofences different colors, but I did it quickly and forgot.


So with that, let’s go with a quick play-by-play of the race.  You initially saw me turn on the units while in the transition area at about 1:10PM (Eastern, 11:10AM local).  Because we were within the TransitionArea-SwimToBike geofence that I had set up, it alerted on my ‘entering’ that fence.  I could have set up exit alerts as well – but I only did that for transition, and not for the general mile markers.


Once powered on The Girl and I simply placed the small units in the back pockets of our tri tops.  About the size of a pack of gum, they were easily out of the way.  Additionally, since they’re IPX7 waterproofed, there was no concern with them hanging out in the water for the 30-ish minute swim.  Now technically IPX7 is 30m at 1m deep, so I would have been just barely over the limit, thus I was hopeful it would work out – but for an Ironman, a simple Ziploc baggie would work to extend the time.

With that, into the water we went.  While I was in the water, I don’t believe the tracking worked – though, with the giant geofence I had set up over just about the entire lake area – it was highly unlikely it was going to trigger an alert unless I swam far off course.

For those following, the first real alert most of you got was when we exited the transition area and then a bit later hit Mile Marker 5.  You probably first saw The Girl’s alert, and then my alert following shortly thereafter– as she started about 13 minutes ahead of me:


It should be noted that the GTU 10 doesn’t actually alert to Twitter directly.  It can only send alerts to e-mail or via text message.  Instead, I borrowed a trick from the Boston Marathon post and used Twittermail.com to in turn relay messages from the Garmin site to Twitter.

Now, what’s unfortunate here is that the Garmin GTU site doesn’t allow me to publically share mapping location on the site.  Other services such as Spot and similar allow you to create shard pages – kinda like one-time credit card numbers, that you can share out temporarily (or permanently).  The only way for someone to see mapping information today is if I give them my username and password (in the IT world we call that ‘less than ideal).

That said, with the help of the username and password our family and coach were actually able to follow along on a map as well – seeing exactly where we were.  In fact, our coach was watching as I slowly caught up to The Girl and when we passed each other (we were actually climbing up the longest climb of the day at the time):

222 Trading Places220 in sight

For the rest of the bike, based on what I saw in the Twitter feed afterwards, the tracking seemed to actually work pretty well.  It clearly showed me hitting the various geofences, and then The Girl hitting them a few minutes later – in the case of the below, Mile 35 (remember, the fence had to be split on the out and back course):


Once onto the run though, things got a bit messier.  See, in theory the course was supposed to be almost a perfect loop – one that you’d do twice.  We were to stay on opposite sides of the river for each loop – allowing me to easily define the geofences accordingly (the course map, and then my geofences):


The problem was…the race decided to deviate from the published course maps – instead, utilizing the following route:


As you can see, this means that when I was supposed to be on one side of the river (southern side coming back), I was actually on the northern side – thus tripping all the carefully laid geofences, creating what was likely plenty of confusion for you.  For example, in the below timeline you can see that it’s pretty unlikely that she ran 6.5 miles in 23 minutes.   Unfortunately, due to the course change, she doubled back through the 5.5 mile marker zone – thus triggering the alerts.


Now, I can’t fully blame the GTU 10 for this – that lies within the realm of the race organizers.  However, should the GTU 10 had the capability to both show actual GPS track as well as current location publically, this would have been more clear and understandable.

That said, on the whole, the GTU 10 did provide a pretty useful way of tracking us.  And for my family that had access to the web page (or the dedicated iPhone/iPad app), they could pinpoint exactly where we were, any minute that they wanted to.  And had this been a full Ironman distance race – the mapping and location data would have been incredibly useful for family and friends, especially given the comical availability of data/splits from sites like Ironman.com

There are however a few suggestions I have that would take this from an interesting experiment to an amazingly useful tracking device:

1) Create/Allow the user of a shared web page so that in the future I can just give out a web page to see where I am.

2) Allow me to overlay a GPX/KML file of the course onto that page – this way folks could see where I was going.  The above screenshots from the maps are nice – but my family and friends had to cross reference that with MapMyRide.com/MapMyRun.com routes showing where we were going.

3) Track my track history. Since the device is using cell phone technology, the data rate costs are considerably cheaper than satellite based upload services – and the data files associated with it are small.  The unit could simply record the track internally and then occasionally upload the full details, even if the recorded route uploaded every few minutes it would still be small data-wise.  That combined with #2 above would make a world of difference to more than just sports folks such as hikers and the like, allowing friends and family to see if they’re on track.

4) Upload ANT+ data.  Sticking a $2 ANT+ CC2571 8-channel receiver chip inside and uploading the associated data would turn this device from a general purpose one into probably the coolest sport tracking option out there.  Sure there are cell phone apps that can do this with dongles (or the Sony Ericsson ANT+ Android phones) – but none of which can last a half-iron race (or an Ironman) and none are waterproof.

Beyond those four items, everything else worked rather well.  The alerting system is lightning quick, and the accuracy impressive – as was also noted in the Boston Marathon post.  Plus, when you tweak the names a bit on the tracking devices (as I did), the alerts it generates can be pretty funny…and oddly accurate.  Thus, I leave you with two of my favorites:


So for those following along – how did it work?  And any suggestions for either myself or the folks behind the GTU 10?


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  1. Great write up. Question: does Garmin still do research and development in the fitness market? Or do they just read your blog?

  2. tms

    Sounds like an interesting little device, and if they made the changes you suggested (the public maps being most important) it’d be incredibly useful. Aside from racing uses, it’d be great piece of mind for long solo rides.

    Integrating an ANT+ radio would certainly help increase the value, especially if it could integrate with their other offerings (ie add menus in the Edge 500/800 to configure it in the field). $200 is a bit on the steep side for simple position reporting, but it’d be a no brainer if it could report full real-time telemetry.

    Now they just need to negotiate with the carriers in Canada so we can join in on the fun ;)

  3. Hey Ray,
    I was following twitter on my phone most of the day. It was interesting to see the updates. I couldn’t tell but, they seemed to be a little behind. It was also interesing to see you closing in on the girl in the updates and then you could tell you passed her.

    I agree with you on having public maps but, it doesn’t seem like Garmin intended it to be used in this way. Although it would be good to see them adapt to the way people would like to use it. It would be cool if they could have it communicate with other Garmin devices and display your time, pace, altitude, mileage, etc…

    An iphone app for real time location on a map would also be great.

    I’ll probably end up getting one next year for a half-ironman/ironman…all because of your reviews. Same thing with the 310XT, I may have never bought one if I hadn’t read your review.

  4. Ray, if you upgraded to the more expensive tracking package offered by the GTU 10, would that make any difference?
    I have one myself and have been instructed to keep it on me when I’m out training…apparently an occasional crash makes people worry.

  5. Let me first start by saying congrats to you and The Girl. Well done!
    Worked Great as far as I could tell. Is this something that might be for sale soon? I would love to have something like this for Marathons. In the 2010 Marine Corps Marathon, they had a sorry excuse for runner tracking on an iPhone app.

    Look forward to your response.

  6. This comment has been removed by the author.

  7. So I first read your blog when you talked about the EDGE 800. You had mentioned that one of the cons of the 800 was no wireless connectivity, and I thought, “What’s the point?” Now I see what it is, which leads the next question, are they planning on adding the GTU function to the next EDGE line?

  8. Anonymous

    Have you looked at sites like endomondo.com, which offers both real-time tracking and uploading from files or directly from Garmin devices? They offer apps for every smartphone out there, from Symbian, iOS, Android, etc. It does require you to carry your device with you (I wouldn’t do it on a swim), but it’s pretty cool

  9. Gave you my comments on the tracking below your race report.

    Your idea of an Ant+ chip is pu genius. They would sell so much more of these units.! I would definitely get one straight away. (I think I’ll end up getting one anyway)

    One question: I know the unit does not keep a track log, but does the website?

  10. Honestly having to set up geofences makes this devices almost useless. Let’s say I just wanted to carry the GTU 10 with me on my long ride, so family members can check in every now and then to see where I am. I’d have to set up geofences before riding? Or am I missing something. I’d DEFINITELY be purchasing them for myself and my husband if people could simply have access to a map to follow along.

  11. great write up – FYI I have been using this for cycling and it works well – see my ‘daves’ review on amazon.com for more detail about the difference between the two plans .. and Alison if you see this, yes your family can track you while you ride.

  12. Scott Timmons

    Last night after talking to my wife about getting the GTU 10 and the benefits it would offer for tracking my long distance bike rides, runs, and races I finally decided I was going to purchase one. Today I went to Amazon.com to buy it. The phrase (Discontinued by Manufacturer) followed the product’s name.
    I called Garmin’s support for the GTU 10. I asked if it was being replaced by a newer model. The representative said she didn’t have any information of a newer model. What gives? I’m hoping that there really is a new model coming out and that they didn’t simply drop this type of tracker. Although the representative said they will still support the GTU 10, I didn’t purchase it. I’m hoping there really is a next generation model. I’ve been searching for another type of gps athlete tracker and haven’t found one yet.

    • They’ve kinda quietly discontinued it. Mostly because both the latest Garmin Edge (cycling) and Garmin Forerunner (running) units now have Live Tracking connectivity through the cell phone.

  13. Justin

    Do we know if there any comparable products out there, that are doing this sort of job? I’d be keen to purchase some thing for training and racing.

  14. GailM

    I’ve been looking for a GPS device so I can track my husband while he’s doing an Ironman this autumn. I’ve been recommended the Spot Gen3 which he would wear, and I can follow his realtime progress via an app on my phone. Whether it would provide the sort of data you’re looking for I’m not sure.
    link to findmespot.com

  15. Jerry

    When renewing the tracking (dec 2014), I noticed that Garmin says tracking ability will stop in Jan 2016 with no plans for a subsitute. I use the GTU10 mainly for tracking our auto; just leaving it pluged in & on. Garmin Edge/Forerunner tracking isn’t really the same thing. Anyone know of a GTU 10 replacement?

    • Not a lot of good options that are multi-use like the GTU10 unfortunately. There’s ones that are sorta specific like the Spot trackers, which is about as close as you can get. Or, sport-specific like the Bia watches.

  16. Joaquin

    Is it compatible with Garmin edge 810? I mean…
    I do not want to use my mobile phone for live tracking.
    Could i connect both devices (810&GTU 10) in places where my phone is out of order cause there is not Movistar/vodafone/Orange signal?
    I will being connected through GTU unit as well…!

    Is it possible ?
    Thanks :)

  17. Ken Polleck

    I was so excited to find this article because I was going to find and dust off my Garmin GTU-10 for my first upcoming Half Ironman–not wanting to take my cell phone on the bike but wanting to let family and friends know I am still moving–and then I found this: link to buy.garmin.com — “Due to changing circumstances, the third party services necessary to support the operations of your GTU 10 tracker terminated Jan. 1, 2016. As a result, your GTU 10 is no longer operational. We apologize for the inconvenience.”