Forerunner 645 Speculative Specs – September or October? Evolution or Revolution? – SPECULATION NOT a Review

Source: Garmin (S60)

By mid-October we should see the new Garmin forerunner 645. That will be the optical HR replacement for the top-end Forerunner 630 (r. Oct 2015). We might even see it by mid September.

We might also even see it released in parallel with a Forerunner 245. That would be nice.

Please note that this is speculation and NOT a review in any form. This follows on from an earlier speculative piece in July 2017 and this one last month.

Here’s a summary of the fairly obvious with my guess, in brackets, of the likelihood:

  • (100%) It’s a running watch. For running.
  • (100%) It will have ALL the running-related functions we know about on the Fenix 5/935. So that means things like the new Firstbeat metrics.
  • (30%) It might have a new running-specific feature eg STRYD support (not so sure about STRYD) YES !! 100%
  • (30%) it might have a new running-related feature eg onboard music (I suspect not as that is not in the Vivoactive 3 and such a feature would also need to find its way to the Fenix 5 pretty sharpish) YES !! 100% on one version:
  • (60%) It might have a new trending feature such as Garmin Pay support (reasonably likely)
  • (20%) It might have other existing high-end features ported to it eg MAPS (like the on the Fenix 5X…but I doubt it). Maybe there will be some half-way house with a prettied-up breadcrumb view overlain with an extract from a map? Imagine the 14th hole displayed on the S60 and remember than Garmin has recently re-vamped the COURSES functionality on CONNECT.
  • (100%) It will be kitted out with the latest, existing sensors so we are looking at the supposedly improved ELEVATE optical HR sensor for 247 monitoring, as well as the Mediatek MT3333 GPS+GLONASS chip
  • (20%) It could exploit new features of those sensors eg GALILEO on the MT3333. This is not as far-fetched as it sounds as we now half-expect GALILEO support in some form or other in 2018 introduced into the Fenix 5 and Garmin already support Galileo in the FORETREX.
  • (90%) It will support re-broadcasting of HR form ELEVATE
  • (100%) It will do other stuff like cycling but won’t have high-end non-running features eg power meter support. ie it will NOT be a triathlon watch.
  • (100%) It will benefit from the new workout and course functionality introduced recently into Garmin Connect
  • (100%) It will support Samsung SmartThings
  • (100%) Bluetooth sensor support – that’s HRMs and foot pods
  • (90%) Barometric Altimeter. YES !! 100%
  • (80%) Touchscreen


I know , I know. It’s probably all nonsense and I’m making it up even the SmartThings compatibility…or am I 😉

Source: Samsung via @Joop


or not 🙂

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Jonathan.JustinKatJoopthe5krunner Recent comment authors
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After releasing the Vivoactive 3, the only difference between top models like fenix 5 or 935 is “almost” the design and battery life. But for us, casual users, Vivoactive 3 is like Fenix 5 light version and the FR 645 should be extraordinary then 🙂 I hope….

John Kissane
John Kissane

Looks interesting, might make consider moving on from from my 620 if the price isn’t crazy high.


I think you’re quite right about the expectations for the Forerunner 645. I hope it will support power natively (Stryd to be precise). I wonder though whether Garmin will support Stryd; it can be a lucrative market they want to have for themselves. The fact that none of the “recently” introduced watches (Fenix and Vivoactive) supports it, might be a sign.

In the Samsung Smart Things link was also a Fenix 5 plus. I am wondering what Garmin will propose for that watch. It is be a bit strange that a plus version would be presented only half a year after the Fenix 5 was released.



Do you think that the Forerunner 245 could be released in time for the Chicago Marathon on October 8? I am in desperate need of a running watch but it would be a shame to buy the 235 now when it’s so close to the end of its life cycle… then again I wouldn’t want to run the marathon without a watch at all…



I truly hope the 645 will be a touch screen forerunner. I have a Vivoactive HR+ and can’t imagine pressing buttons to navigate menus/screens. Althought i wouldn’t mind if it has touchscreen AND had buttons. I really want to upgrade to a Garmin with more advanced HR info and running dynamics and capable of accepting (uploading) training plans.