The difference between the F5x HR and HRM-TRI is night and day...

You are aware that optical HR is pretty much useless for sports other than running/walking and measuring resting HR, right? Get a Scosche Rhythm+ if you want to have relatively reliable readings for cycling as well.

You are aware that optical HR is pretty much useless for sports other than running/walking and measuring resting HR, right? Get a Scosche Rhythm+ if you want to have relatively reliable readings for cycling as well.

Well its just sad that a Fitbit with barely any sensors and cheap quality provides better data than the F5x without any strap ;)

http://imgur.com/a/RRJT5

Clearly Garmin is lacking in the software/algorithm side, just like how the F5x can't track sleep properly.

Hopefully Garmin continues to make this great device better.

My 5X even struggles with optical heart rate when just walking- keeps saying my hr is up at 140 on a gentle stroll!!

My 5X even struggles with optical heart rate when just walking- keeps saying my hr is up at 140 on a gentle stroll!!

While I don't have a 5X (heavier), I do have a 5 and I've noticed that as well. On walks and hikes, it seems the watch struggles with optical HR. When I've compared the f5 OHR to my Spartan Ultra and Scosche Rhythm+ on a run, the f5 is lots better.

Here's my theory: when walking and hiking, more than likely arms are in more of a down position than when running. I'm thinking that since the watch in this down arm position isn't being held by the straps the same as when running, there's greater chance for the watch to lift and lose HR lock. I don't know how to illustrate this via text, so mimic your arm position when running. Most likely your forearm is parallel to the ground, or close to it, right? Now, think about how the watch is being fully supported by the straps in that position. Not much play for it to lift off skin. With your arm pointing more to the ground the straps are holding the watch in place, but the watch body can lift off skin easier. You could counteract this by tightening the watch even more, but then you're possibly into numb hand territory.

I've had no problem with it losing lock while hiking and such; basically anything other than running. I do use a strap for running, but that's because I want the advanced run dynamics and don't have a reason to pop for the additional "pod." If I knew someone who had it I'd give it a try and see if the OHR works acceptably while running for me.