the Garmin Forerunner 310xt attached to my bike's saddle bags

I’ve been highly desirous of some sort of waterproof GPS tracker for my swims ever since I read about the one my buddy Sully out in Ohio has. These types of things are pretty expensive though so I never quite went as far as to buy myself one… fast forward to Christmas and all of a sudden I have a Garmin Forerunner 310xt! Yay thanks mom :)

off to the farm fields in the name of science!

So in the name of science I went for a short bike ride and a short swim to test it out. My bike ride was just a 5 mile loop and I attached the GPS to the straps on the saddle bags on my bike (can you tell I’m a serious roadie by my rack and bags, haha). The tracking on my bike ride was pretty much spot on. If you check the map there’s a little gap missing at the beginning, but that’s my fault I wanted to try and change a setting and had to reset it within the first 10th of a mile.

click for more details like speed, elevation, etc

After taking a few minutes to check out my findings I packed a swim bag and drove up to SLO to try this thing out in the pool. My gym in SLO has a 50m outdoor pool, so even though that’s not where I intend to actually be using this thing, I figured it was a good place to do a somewhat controlled test.

This one wasn’t quite a success, but it wasn’t quite a failure either. With these GPS things you can’t wear them on your wrist and expect to get a signal from underwater… not gonna happen. So I surgically removed the watch straps and jammed it up in my swim cap. I swam about 500m normally and then took the unit out of my cap and kicked 100m so that I could watch the meters add up.

sort of on target with 2 major errors in there

Fun fact… my top speed was 86 miles per hour! How about that! I’m going to say that my initial satellite hook up placed me a little off course. I swam 600m but was credited with about 820. Alright free meters :)

I’m hoping to take this to the ocean with me Tuesday or Thursday to give it a chance to work out in the open water. I think it will deal with that a lot better than it would switching back and forth on the same line in a pool. I’ll keep experimenting and keep you guys updated! In the meantime I need to make some modifications to hold it too my goggles more securely so it doesn’t drift off to a watery grave in the case of a wave ripping my cap off…

my laboratory

7 Responses to “Experimenting with the Magic of GPS”

  1. IronMike says:

    I am so glad you try all these cool gadgets out before I buy them. Thanks!

  2. Lorraine says:

    I love your careful equipment evaluations. You were an influencial reviewer when it came to getting an underwater camera; seeing the shots you got at Big Shoulders was the first “wow” moment. We got a Lumix DMC-TS2 as Christmas present from me and husband, to me and husband and after a playful hour at the pool, I LOVE it!

    But, to the subject of Garmins: I’ve used a Forerunner 305 for several years biking/running before a swimmer told me – hey, put it in your hat for swimming. (Duh.) I set it to vibrate at certain intervals –nothing like a buzz on your brain in the middle of a favorite lake to make you smile big. I can’t compare accuracey absolutely but kayakers with a Garmin confirmed distance was pretty close.

  3. Rob D says:

    Mike – it’s a public service I provide :)

    Lorraine – thank you :) I’m glad you like the Lumix so far, it’s been a solid performer for me the last couple months… hopefully it continues to do so! I can’t wait to get in a few ocean swims with the Garmin to see how it performs in the ocean. Since we use a lot of fairly fixed points to navigate off of on our swims I should be able to compare the data with Google Maps to see about how close things are.

  4. bryan says:

    I tested out the Suunto GPS pod on an open water swim and it worked wonderfully until I caught a wave coming back in :(
    So if your open water experiment includes surf- be sure to batten it down securely to avoid said watery grave :)

  5. Rob D says:

    I’m thinking there will be some velcro and super gluing in store for my Garmin in the near future… I really don’t want to lose it to the ocean!

  6. Lynn K says:

    Glad I got to see this…what a GREAT idea to test it short range in a pool.
    When I calc OW distances I do what I call a “poor man’s Garmin”. That would be the path-tool in Google Earth. I think it is good for rough guesstimates for USMS “Go the Distance”.
    Thank you for sharing this!

  7. Rob D says:

    Lynn – I use the distance tool on Google Maps a lot to figure out how far my swims are, this is way fancier though :) So far my open water tests have been way more accurate than the pool swim although I do manage to pick up some elevation gain in water occasionally which strikes me as a little not correct!