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Forerunner 245M vs Forerunner 645M Advice

ajmurg
over 5 years ago
Looking for some advice from some seasoned Garmin runners please.

Currently running about 35/40 miles a week, compete in anything from 10k to the occasional marathon, may look at an ultra next year. Mostly road, no real interest in trail running. Odd cycle here and there but that's about. No swimming.

Have for the last year or so been using an Android Wear smartwatch linked to Strava for my runs but need to switch out due to the fact it's basic, the battery life is no longer sufficient (started cutting off runs etc) and I HATE the fact it's touchscreen, especially in the wet. I'm also just starting to get into reviewing and understanding various metric data available.

Therefore looking at a step up to a proper running watch to aid me with training. Had previously discounted Garmin's as I want something with internal music playback and those with that feature were too expensive, however saw the initial reviews for the Forerunner 245M were positive, and then that the price for the 645M has dropped as well. Have discounted Vivoactive 3 due to touchscreen.

My needs are primarily standalone music playback, battery life (which appears to favour the 245M), ability to have training runs on the watch (both), sleep tracking (both) and longevity with price ultimately coming into it as well.

From what I can tell, the 245M benefits from updated innards, improved sensors, and 3 extra FirstBeat metrics. The 645M has the barometric altimeter (which given I don't do huge variations in elevation maybe isn't important) and Garmin Pay (which despite criticisms of it I would actually use as I have a compatible bank account) as well as some other things that I don't care about.

It appears to me that the 245M is the more feature-rich watch training-wise, but given I've only just got into metrics I don't necessarily have an understanding of what some of those additions entail. Whereas on the 645M the addition of the barometric altimeter and Garmin Pay are tangible additions which I can quantify.

If both were the same price, I would likely go for the 245M, however I can currently pick up a 645M for about £260 (has been as low as £240 recently) against circa £285 for the 245M.

Does anyone have any real world thoughts/advice? Will the training additions on the 245M outweigh the tangible benefits of the altimeter and Garmin Pay? One of the things that did concern me was the battery life on the 645M as some of the reviews criticised it quite heavily (although I note it still states 14 hours with GPS and I'm NEVER going to run for over 14 hours).

Any comments gratefully received.
  • 0 over 5 years ago
    I think between the two I'd personally go for the 245M because of the additional metrics.
    However, as it is just out, you'd be the early adopter and also pay a too high price. If you need the watch now and don't want to wait, go for it... otherwise... what about a used 735XT or 935? I have no clue where they are price wise, but just as an idea.
  • 0 over 5 years ago
    Thanks for the comment. Did look at both 735XT and 935 but neither have music playback which is one of my requirements. Have updated my original post for clarity on that.
  • 0 over 5 years ago
    Also looking at either of these. I think the 245 will fill in the gaps my Apple Watch leaves. Don't forget dc rainmakers 10% discount from clevertraining.co.uk brings the 245M down to £269.
  • 0 over 5 years ago
    Also looking at either of these. I think the 245 will fill in the gaps my Apple Watch leaves. Don't forget dc rainmakers 10% discount from clevertraining.co.uk brings the 245M down to £269.


    Yeah spotted this, which brings the difference between the two to £10 so practically nothing. Said originally if they were priced the same I'd go for the 245M.

    Have also been reading about numerous problems with the 645M's altimeter so for essentially the same price I think the improved battery, updated sensors and extend metrics of the 245M outweigh the benefit of Garmin Pay on the 645M.
  • 0 over 5 years ago
    From what I can tell, the 245M benefits from updated innards, improved sensors, and 3 extra FirstBeat metrics.


    It's actually just 2, I believe. Early, we had Respiration Rate listed on the FR245 device page, but that was a mistake … probably mine, actually. Sorry!

    The 2 features on the FR245 that aren't on the FR645 are Body Battery and a new Race Time Predictor (which is actually kinda cool if you are into that sort of thing). The FR645 has a race time predictor, but it was just a simple look up table based on VO2max and general expectations for performance sustainability across various intensities. You can catch up on the new Race Predictor, here (https://www.firstbeat.com/en/consume...ime-predictor/).

    I'm trying to think what else is different, behind the scenes.

    Ah, the 245 doesn't offer the heat/alt acclimation feedback like the 945, but the analytics engine that indirectly measures VO2max has been updated to recognize and account for the affects of heat/humidity and altitude on your performance. That means better feedback for you in more challenging / changing conditions. In addition to more reliable feedback in challenging conditions it also helps improve the reliability and meaningfulness of things like Training Status that needs good input to provide sensible feedback.

    Also, the Recovery Time Advisor is updated to reflect increased/decreased recovery needs based on changes in your acute:chronic workload ratio (7d vs. 4w avg), which is something that sports science nerds are really keen on these days… and also you'll get a longer recovery time prescription for workouts that are significantly harder than the ones you normally do… so, for example, say, most all of your workouts produce a TE of 2.5 - 3.5, then you do a hard 10k race and end up with a TE of, say, 4.6... your watch knows that you'll probably need longer than normal to bounce back from that exceptionally hard effort.
  • 0 over 5 years ago
    It's actually just 2, I believe. Early, we had Respiration Rate listed on the FR245 device page, but that was a mistake … probably mine, actually. Sorry!

    The 2 features on the FR245 that aren't on the FR645 are Body Battery and a new Race Time Predictor (which is actually kinda cool if you are into that sort of thing). The FR645 has a race time predictor, but it was just a simple look up table based on VO2max and general expectations for performance sustainability across various intensities. You can catch up on the new Race Predictor, here (https://www.firstbeat.com/en/consume...ime-predictor/).

    I'm trying to think what else is different, behind the scenes.

    Ah, the 245 doesn't offer the heat/alt acclimation feedback like the 945, but the analytics engine that indirectly measures VO2max has been updated to recognize and account for the affects of heat/humidity and altitude on your performance. That means better feedback for you in more challenging / changing conditions. In addition to more reliable feedback in challenging conditions it also helps improve the reliability and meaningfulness of things like Training Status that needs good input to provide sensible feedback.

    Also, the Recovery Time Advisor is updated to reflect increased/decreased recovery needs based on changes in your acute:chronic workload ratio (7d vs. 4w avg), which is something that sports science nerds are really keen on these days… and also you'll get a longer recovery time prescription for workouts that are significantly harder than the ones you normally do… so, for example, say, most all of your workouts produce a TE of 2.5 - 3.5, then you do a hard 10k race and end up with a TE of, say, 4.6... your watch knows that you'll probably need longer than normal to bounce back from that exceptionally hard effort.



    Hey HermanB, I have never tried the Firstbeat stuff and am interested in it. I am an Apple Watch user who had also a Garmin Instinct (no FB features) but returned it for various reasons. I am looking at getting a 245 for my sporty stuff and wondered if the day HR info captured on my Apple Watch and uploaded to Garmin Connect would register with the Firstbeat software, I obviously don't want to go around wearing two watches at the same time!
  • 0 over 5 years ago
    I think it would be interesting to know if the updated metrics like the race predictor will also come to the 645m via a firmware update
  • 0 over 5 years ago
    It's actually just 2, I believe. Early, we had Respiration Rate listed on the FR245 device page, but that was a mistake … probably mine, actually. Sorry!


    Ah that's a bit disappointing as that was one I would almost certainly have made use of. I've already ordered a 245M now, oh well.

    As per the previous comment is there any chance of firmware updates to bring further FirstBeat metrics, either to the 245 or the 645? I couldn't find anything suggesting there'd been one previously.
  • 0 over 5 years ago
    Ah that's a bit disappointing as that was one I would almost certainly have made use of. I've already ordered a 245M now, oh well.

    As per the previous comment is there any chance of firmware updates to bring further FirstBeat metrics, either to the 245 or the 645? I couldn't find anything suggesting there'd been one previously.


    I assume Lactate Threshold is still coming.... ?
  • Former Member
    0 Former Member over 5 years ago
    Why?