Polar Grit X – I never knew that

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Polar Grit X Review Specifications

Here are some relatively interesting but obscure things about the Polar Grit X. All the things you really need to know are linked here in the snappily-entitled post “Polar Grit X All you NEED to know“. The post, below, is the stuff you don’t need to know but might want to know if you are thinking of buying one.

Here are a few relatively unimportant things then. Please suggest more trivia and I’ll add to the list.

  • There is a permanent ‘ON’ backlight setting for when you workout
  • STRYD seems to work as with the Vantage V. ie you can input a manual calibration factor and all the rest of it.
  • Not all 22mm straps will work sweetly with the Grit X. I’ve tried a few from different manufacturers and the diameter of the 22mm pins vary. Most seem to fit the Grit X to some degree but some of the thinner ones wobble a bit in the hole and do not feel 100% secure. Conversely, the Polar strap’s pin is a bit too thick for my Amazfit Stratos. #FirstWorldProblem. The Polar straps are nice quality.
  • Dual-sided bike power meters appear to be correctly added up to get a total. However, only the total can be seen in FLOW..no LR split (at least not with ASSIOMA).
  • There is a LR power metric on the watch, this would require LR being transmitted over BLE by the PM (just because it transmits it over ANT+ doesn’t mean it will over BLE)
  • Hill splitter seems to work on most (all?) run and bike profiles. Whilst it DOES seem to nicely recognise uphill and downhill slopes correctly it doesn’t recognise non-continuous hills ie where a 1000m total climb is made up multiple up/down sections…or a 100m one 😉 like this


  • The grade/incline reported on FLOW might be wrong. I didn’t get anything above 1 & 2% on the ride above.
  • You can’t see the ambient temperature on the watch AFAIK. However, it is saved and visible on FLOW. It seems to affected by body temperature. You’d have to use a chest strap and wear it over clothing to perhaps get a better reading.
  • You can manually calibrate altitude from the full-screen altitude page whilst in a workout. #Nice
  • Syncing new Komoot or Strava routes to the Grit X is super quick…like it’s pretty much instant to get them to flow. The subsequent sync to your watch will vary in duration.
  • The breadcrumb route following is relatively basic…but functional. If your route goes from A to B to C to D then to B again and a few repeated laps then, well, Grit X will get confused. A to F via BCD and E is cool.
  • You can start a route even though you are not on the route. However, Grit X really likes you to properly find the route but will point you to either the mid-point or start of the route to get you started. Once you find the point on the route, all will be good…in a breadcrumb kinda way. FWIW: That’s fine for me almost all the time
  • When you press the button the internal vibrator does a tiny little buzz (not the button itself). Very exhilarating (works well)
  • The cardio Load screen is shown below. Cardio load takes, I think, about 5 days (7?) before it appears on the watch. Some of the Polar displays, like this one, look quite quirky but, they are generally quite good at getting over the key numeric info IMHO.
  • When anyone says ‘IMHO’, they’re usually not being humble. I digress 😉

Polar Grit X Review Specifications

  • Pressing and holding the top left button locks and unlocks the screen.
  • STRAVA Live Segments requires a premium STRAVA account. I can’t remember what they’ve called it this week. I’ll stick with premium. Whilst Grit X has its own menu option that merely tells you how many run/bike segments are sync’d to the watch, to actually use the Live Segments feature you need to enable the STRAVA screen from FLOW. Although it should be on by default. Like this…

  • Grit X really can use Galileo and the Far Eastern QZXPFGRDQSZ constellation (or whatever it’s called…it has a ‘Q’ in it for sure)
  • Warning: Galileo may eat quite a bit of battery. (I think it does from what I’ve seen but haven’t quantified it yet).
  • GPS+GLONASS might be best to use and GPS-only is not available, which is strange as I would have thought that would save some juice.
  • Basic phone notifications seem to work quite well and are shown very quickly after the phone is aware it needs to send one (iOS)
  • Swim stroke detection probably works as well as the Vantage but no-one has any idea. I think I’ve forgotten how to swim. It must have been a month now. (2020 lock-down for future readers)
  • Zone Lock is an AWESOME feature. Once your pace/HR/power is within any given zone you press and hold the middle button and are alerted if you then try to leave that zone. Especially on longer easyish runs/rides, this can be a much easier way to do zone-based training than faff about beforehand making a structured workout and syncing it to your watch. Zone Lock is great as you can stop or start it easily and whenever you want
  • The LEDs on PRECISION PRIME are a different colour to those on the Vantage. Make sure you choose the right LEDs on the right Polar watch to match the colour of your favourite running shirt 😉 #Important…errr
  • The compass requires you to be a contortionist to calibrate, although it has quite a fun game where you (literally) have to roll a ball across the screen to hit various segments of the edge of the screen. Hit them all, do some more contorting and the compass is calibrated.
  • You can also lock the compass on a bearing
  • You can press pause and change the various settings during an exercise eg POWER settings or BACKLIGHT permanently on.
  • Polar FLOW also links to RELIVE. You can replay a video of your run/ride on a map and it highlights some of the notable performances, like here where I touched on 656w for about 0.1 seconds. I’m claiming it was a recovery ride and I’m going to stick to that story 😉

  • Polar Grit X is a recommendable watch. It’s good in the right person’s hands.

What’s your favourite Vantage/Grit ‘tip’?

Back to: Main Review

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Is it possible to load a route whilst in an activity? Say you are doing a trail race but somehow the course markers have been removed by someone and you have the course on your watch but didn’t have it loaded from the start. I know Vantage cannot do this but Garmin and Suunto can. Is this possible on Grit X?


During navigation-does it show screens like “please calibrate compass” when you stop moving and “do you want navigate opposite direction” and you need to click “no”? Thx!


500€ for something that is really basic… The guidance is below poor and the statistics, really bad… Is just a Vantage V with a new name.


You say the reported grade/incline might be wrong. What about the total elevation gain, i.e. how accurate is the altimeter?

My non-baro Suunto is the pits in that respect; it claimed 7m for this morning’s run while Strava corrected to 20m and Stryd said 30m. I suspect Stryd comes closest to the true gain.


No worries! At least now I know you’ll be talking about the issue.


The incline in flow is in degrees while it is percent on the watch. Once you do the conversion, it matches. But it’s a bit strange not to keep the same unit.

Mariusz Luczak

Hi, can you also check if it’s possible to charge the battery during run? Simple scenario, you are at the aid station for 20 minutes during long ultra race and charge it from power bank while you are there.

tfk, the5krunner

i started a session
I plugged the usb into the GX and computer
computer recognised the GX but obviously couldn’t sync
GX kept the timer going.

tentatively it might be able to be charged. i couldn’t see any charge indicator (I could probably add the watch face as a screen and see it on there maybe)
you know you can use something like fitfilerepair tool to combine fit/tcx files?…much safer if you record your run in two parts and charge in between.



Can fitfile repair handle files from Stryd? Unfortunately the demo version is crippled enough that you can’t do anything meaningful with it (dummy values all over the second half of every file), and in the table columns it displays I don’t see anything except power that very obviously comes from Stryd.

tfk, the5krunner

how do you mean from STRYD? stryd doesn’t really produce files. (I assume you dont mean export from powercenter)

i THINK the answer to your question is:
“yes” it handles FIT developer fields in FIT v1 or v2.

i struggle to think what it CANNOT do. it is very comprehensive…i use it every week. it’s a bit slow with large files but has saved the day many times for me.


I mean exports from PowerCenter, yes — specifically, the ones you get from offline syncing Stryd i.e. independent of any watch data). That’s where all the leg spring and form power stuff is that Suunto watches don’t process, as well as Stryd’s own elevation data (which is orders of magnitude better than that from my non-baro Spartan).

PowerCenter sometimes doesn’t merge offline sync files with watch data files and I’d like a way of doing it manually. But fitfilerepair is a bit pricey to buy before I’m sure it’ll do what I want.

tfk, the5krunner

i’ll ask stefan the developer to reply

what is your end purpose. i don’t see what you are trying to do.
movescount/suunto wont let you see the extra stryd data.
if you are exporting to a spreadsheet then you can do the merge in the spreadsheet


Couldn’t reply farther down the conversation, a couple of tips I’ve learned with Stryd.
First, their customer service is EXCELLENT! If you need a file merged in Stryd, or the “watch and Stryd data don’t sync”, let them know, and they’ll (typically within hours in my experience, or faster) do that for you.
Second – This is a tip I learned from them… if using Stryd “Offline Sync” make SURE that your watch data syncs FIRST, and is showing up in Stryd app and PowerCenter. Only THEN once the watch data is there, sync up the Stryd pod. I was losing about 1 out of 4 syncs (requiring their help) before learning that nugget (Thanks Hannah!), since doing that, I haven’t had the files go out of sync once (I’ve forgotten maybe twice since then and synced the Stryd pod first absentmindedly (post-workout brain) and not had issues, but I primarily do the “Watch, wait, make sure it’s in Stryd, then “pod”, and it’s been bulletproof.
Anyhow, hope that helps some!

tfk, the5krunner

great one Chris


Yes, that workflow does the trick every time. Problem is it can take forever for the watch data to sync to PowerCenter (yesterday it only showed up after FIVE HOURS). I wonder whether it would be feasible for them to implement an option in PC to manually force sync from Suunto App (or whatever ecosystem) to speed things up? Usually by the time the watch data shows up in PC my pod has gone to sleep and needs repeated bouncing off the carpet to wake up again for an offline sync. 😀

Mariusz Luczak

I didn’t know about fitfilerepair tool. Thanks for the tip.



the Q…. satellite system is the Japanese one: Quasi-Zenith Satellite System (QZSS), also known as Michibiki (みちびき)


tfk, the5krunner

thank you for the Japanese nomenclature, that clears things up. 😉
i was half-joking about the silly name


Do you know if it will support Beidou?

Suunto testers have said that suunto 9 in beidou mode has its best accuracy

tfk, the5krunner

i dont think so. ive never used beidou


I’d reply to your latest question, but I keep getting a 403 Forbidden error because I’m allegedly making a request to your site involving a “potentially unsafe operation”…

tfk, the5krunner

I’d suggest doing a safe operation, they are always best in my experience

seriously though: i’m maintaining the site….maybe you tried to do something when the site was down for 5-10 seconds

please try again and post me a screenshot please if it fails. it could be adblocker related or browser-related. it all works at my end

if you send the two files you want combining the developer will look at them, he found something strange stryd-related recently by coincidence


Nope, still can’t post my reply.


I mean, I can obviously post SOME things. Just not the content that I emailed you just now!

tfk, the5krunner

if you want to post a .PNG file i think you will have to give the url of the image file (eg a public dropbox folder)
ie i don’t think you can upload it directly to a comment.


I wasn’t trying to upload an image, just post the text!

tfk, the5krunner

ok developer confirms it works you import the stryd file first and then append the suunto file on top.
save them both to whatever format you want.