Garmin Forerunner 405/405cx vs Polar RS800cx G3

A while back I read a Garmin Forerunner 405/405cx review which was pro- the device. This text was intended as a comment on that review, but grew a bit out of hand for a comment. Here first a few words on the Garmin – just for context. Garmin, the word is yours:

“The Forerunner 405/405CX is the evolution of GPS-enabled training. This sleek sport watch tracks your distance, pace and heart rate, then wirelessly sends the data to your PC for later analysis. The 405CX features heart rate-based calorie computation and comes with a second wrist band option suitable for smaller wrists”.
For a comparison on the Garmin Forerunner 405 and the 405CX I suggest you go here:

Now, while all that Garmin marketing and the products themselves certainly do make you think about how you can use one of them in your training, there are a few things that should make you think twice. For instance the battery life of Garmin 405/405CX is not impressive and will require frequent charging. If you go somewhere far away for training or competition, do you really want to have to worry about charging your heart rate monitor too?

If you compare the Garmin 405 to the Polar RS800CX with G3 (GPS) sensor – the premium product from Finnish company Polar you’ll find both pros and cons for both. Let’s start with some of the Polar’s weak points:

  • too many devices: heart rate band, wrist unit, GPS-unit;
  • since recently: the Polar is a very closed platform with no current options of exporting Polar data to other platforms – although I haven’t tested it, the Garmin does offer export to Endomondo and other tools that allow for mapping and sharing of training routes and data through various social networks.

The advantages of Polar vs Garmin are:

  • The disadvantage for the Polar can also be turned against the Garmin: More devices in the Polar solution also ensures that if for instance the GPS runs out of battery during training you will still get heart rate data for the remaining session. Not so with the Garmin where it’s all lights out if the wrist unit dies. Furthermore the Polar’s battery will take you MUCH further than the Garmin battery – probably because the battery doesn’t need to support the same amount of functions.
  • Final comment on the battery: Battery change with the Polar doesn’t happen often, is easy, and relatively cheap.
  • Soft heart rate strap on the Polar. With the Garmin the heart rate strap is hard and a soft is only available for an additional $70.

I’m missing more information on social network integration. The Polar is completely unfit for any type of social network interaction. The Garmin has an own network with a few shortfalls, but more importantly allows exporting training files to services external to Garmin.

Conclusion: For me Polar wins this battle. The shortcomings in the Garmin package are a source of irritation if experienced while training. I have a feeling that I might find myself without battery really often.

Still, one has to often if Polar is fighting the right battles. Presumably the consumer market is where they get most of their money and they might want to watch it more closely and avoid what has happened to the Navigation device manufacturers: Mobile devices with minor additions grabbing market share with free software.

It’s happening in the training device market already: mobile devices from Apple, Nokia, HTC and more now include GPS for positioning and speed data, software for the tracking and uploading, and finally all they need is a 3rd party bluetooth heart rate monitor and off you go. I’m not aware of any heart rate straps that will do the trick, but as soon as they come out, Polar should get worried.

More about that in a future post.

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  1. Nice review.
    The only cons I find with Garmin is the price and the battery. And yet, the 405cx battery looks a way better. It’s rechargeable and if don’t use the GPS all the time, you won’t have any problems at all.
    I’d rather not say anything about Polar, as I have found nothing but disappointment with them.

  2. The Garmin uses ANT+ for communicating with the heart rate sensor and other sensors, so there IS coding (the devices are actually paired to the clock just like with Bluetooth). So interference between athletes will not be a problem.

    1. Hi Kristian,

      Thanks for your comment and for correcting my comment, which I will adapt/remove promptly! Just to be sure I’ve looked it up again and you’re spot on that the Garmin 405 and 405cx use ANT+.


  3. I’m still undecided. Garmin 310XT or Polar RS800CX? I already had 3 Polars in the past. The reason to switch is because of the GPS. Polar is more expensive but the batteries last longer. On the other hand the Garmin has everything in one device, the polar requires you to use the arm band. Not an easy choice to my opinion …

  4. I have been using the 405CX for a year now. It is a truly fantastic device in all respects but one – battery life…
    The garmin web-site application is good and I can export my training sessions easily. It’s compact and user-friendly. very accurate. The battery life was fantastic for the first 8 months but then nose-dived to the point where it wil no longer last for even a 1 hour training session (from full). What a great device – completely let down by that battery…oh well what to do as they say…lets hope the next version lasts longer….

    1. Hi Wayne! Thanks for your response! What do you use the device for? Did you try speaking to Garmin support about this? Doesn’t sound like what they planned for and my understanding is that they’re usually pretty helpful. That said, so far I’m having a good time with the 310XT I acquired this summer. We’ll see what happens after 8 months ;-).

  5. Hello there! I use the 405cx to monitor my motorcycle enduro training. In this activity it is well suited as I also use the GPS to set my way-points and track my route for comparson later on google-maps/earth. I compete in an annnual 5 day desert race called the “Abu Dhabi Desert Challenge”. I would typicaly spend up to 5 hours on the bike in one session. I am now using my ForeTrex 401 which I discovered (with a firmware update) can also track hear-rate. It’s much bulkier but at least the batteries are standard replaceable AAA so they never die on a long session…and with that firmware upate it also works with the Garmin Connect web-tracking application…so it’s all good. I will take the 405cx unit down to our local Garmin agent but am not hopeful – here in the Midle East things work a little differently to back home…on my last ride the battery died at 35 mins from a full charge…

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