Garmin 645 Music

Thought I would post a quick review of this running watch, because I personally don't see any reason why you can't use it for biking (I do).

First, let me confess I have a checkered past with bike computers. I have lost one due to a failed mount when I did a slow-motion OTB on Joplin last year. I lost (but regained) another due to another failed mount when I clipped a tree trunk on a wooded single track this summer. And then I had two that bricked, or locked up, for no reason that I could discern, and even hardware resets did not resolve the problem.

Due to this history, I try to avoid buying the newest and most expensive hardware. I usually set my sights on the last generation stuff, and try to find deals where I can pay a significant discount versus when just released. Currently my default bike computer is a Garmin Edge 520 Plus... a device that released 4/2018. Not that old, but not that new either. It is a decent computer, though not particularly accurate, and I have had some issues getting consistent GPS readings due to tree cover.

Fast forward to my current situation in NC. Due to wet weather, the biking trails have been consistently closed, and so I have been doing more trail running than normal. I tried using the Edge 520 in my fanny pack, but it didn't really do the job because it wasn't that accurate, and having the computer in a fanny pack prevents you from tracking your progress while you are running.

Years ago I had a GPS running watch, but I had to wear a cardio chest strap with it if I wanted to track heart rate. So when researching GPS watches, imagine my surprise to learn that there are now some GPS watches that do a very good job with wrist-mounted heart rate tracking. After reading this review:

https://www.nytimes.com/wirecutter/reviews/best-running-watch/

I decided to give the Garmin Forerunner 645 Music a try. So here is my short review:

Garmin Forerunner 645 Music
Announcement date: 1/2018
Availability date: 3/2018
Purchase date: 1/2021
Suggested retail: $450
Price paid: $270

Ergonomics: Surprisingly lightweight and comfortable. Comfortable enough to wear 24/7 even while sleeping (for sleep tracking and resting heart rate info). Waterproof to 50M. Holds a charge several days, even while using in GPS mode for tracking exercise.

Functionality: Push button interface (versus touch screen) that has stripped down options so you don't spend all your time trying to navigate through numerous screens. GPS pairing is both faster than my Garmin Edge 520 and more accurate. Screens are fully customizable. Backlight is always on when tracking an activity, or can be turned on with the touch of a button when in passive use. One minor downside... backlight can be quite bright if you are running or biking at night and is not adjustable... but I don't typically run at night.

Heartrate monitoring seems accurate, and is consistent over time (my resting heartrate measured over the course of days, as compared to my resting heartrate reported in my health charts by my doctor). Having accurate heartrate adds an additional helpful benchmark for tracking exercise and targeted fitness.

The "music" function was not tested - I do not listen to music during activities.

Surprises so far: Did not buy the watch to wear it 24/7, but find myself doing so. Automatically pairs with my Garmin account via bluetooth, so I don't even need to remove the watch for it to communicate automatically with my PC. Strangely satisfying experience.

As a bike computer:
Wrist mount is a lot safer than having the computer on my bars.
Wrist mount is more difficult to glance at than having a computer on my bars... but not by much.
During rides, vibrates every mile and shows my pace before reverting back to standard mode.
Heartrate tracking huge bonus versus just tracking distance, time and altitude.
GPS more accurate, and locks on faster than my bike computer.

Added bonus:
When I am riding my bike while wearing this watch, my Garmin account thinks that I am actually running. I am now officially a globally ranked ultra-marathoner. Yesterday I "ran" a half marathon in an hour Guilty pleasure... at least before I edit the exercise type

 

Thanks for this!
Great in depth review!

 

Thanks for the intel. I’ve been thinking about a smart watch for awhile.