GPS test | Polar Grit X vs Suunto 9 with BeiDou

2 tests after the last firmware update by Suunto


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The Polar Grit X full review is already published.

This article is only a small test, so if you want to know all the details of the watch, how it works and the my full detailed opinion, click on the following link:

Polar Grit X | Full in-depth review and opinion

One of the things I had to do since the beginning of the pandemic was to test out the new Suunto update. And it was pending since March (we're up to May... wow!), so now that we've been able to train outdoors, it was a matter of checking this out from the to-do list.

The test I wanted to do was specifically about GPS performance. I have not yet had the opportunity to test the improvements in the barometric altimeter, because I can't drive to the mountains yet (we must train in our town at the moment, it's not possible to cross to a different place) and because I would need a few hours run with sudden changes in barometric pressure, which is not something that happens frequently in Marbella.

And since I already talked to you enough about the integration with Training Peaks on the firmware's release day, I only had to comment on the performance of the GPS+Beidou option, which according to internal sources from Suunto it offered a great performance improvement.

Also, as I am in the middle of the Polar Grit X review, I have a great chance of testing both things at the same time.

Since the confinement was lifted I have been able to perform two run workouts in which I have combined the Grit X together with the Suunto 9, of course accompanied by more devices to verify the data. In addition, they are not excessively easy tests because I am running at a somewhat slower pace than usual, because despite having been able to train on the treadmill, it's not the same as running outside.

And why running slower is worse for the GPS tracks? Because by recording location points every second, they are closer to each other and makes the tracks appear uglier, or small errors get more noticed. It is for the same reason that in cycling the tracks are usually so beautiful, because the distance between one point and the other is much greater than running or walking.


Test #1

>> Check it out
GLONASS and Galileo. What is it and when to use it

So I start with this short workout of only 4 kilometers, which was also the second session of the day and the recommendation from my coach was to make it EASY. As I am very disciplined, I did it at a slow pace of 6:28 min/km on average. As I indicated earlier, it is far from ideal conditions for a GPS watch.

For this test, in addition to the Suunto 9 Baro (again, in its latest firmware version and with GPS+Beidou option enabled) and the Polar Grit X (configured in GPS+GLONASS); I also carried the Polar Vantage M (GPS+Galileo) and Garmin FR945 (GPS+GLONASS).

By the way, I just restored the FR945 because lately it was giving me horrific GPS performance.

Comparison GPS Suunto 9 and Polar Grit XThe first impression is really good on all four watches. At least, from a bird's eye view, none of them have deviated from the route and the lines drawn are quite straight. But let's zoom in to see the details better.

This is the beginning of the training, but already advanced a few meters so the signal quality should already be reasonably good. It's not an easy zone because I run under some metal structures that give shade, and they can make a little of a Faraday cage effect.

Comparison GPS Suunto 9 and Polar Grit X

On the Grit X I have already seen a behavior that has been very common in the Vantage M and Vantage V. A slight positioning error, but that persists over time. It is not too important because in the end all you are doing is moving the track 2-3 meters out of the actual location, but the measurement of pace and distance is correct because by persisting in the error it draws a completely straight line parallel to the real track.

I mean, it's not very important, but none of the other three watches have it. Neither does Vantage M, although it is true that its satellite configuration is not the same (GLONASS on Grit X and Galileo on Vantage M).

Later we can see that the Grit X is still committed to moving slightly to the right of the correct route, when none of the other three have. And by the way, I haven't mentioned it yet, but Suunto 9 has been perfect so far.

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Comparison GPS Suunto 9 and Polar Grit X

However in the following image is the Suunto 9 the one that has shifted a bit compared to the other tracks. The area I have pointed out with the arrow is a moment when I get off the road to avoid people walking along the sidewalk (social distancing and such), something that every watch has recorded perfectly, except the Suunto 9.

Comparison GPS Suunto 9 and Polar Grit X

Same thing happens here, I go down to the road to make room and every watch obeys... except the Grit X that keeps making a straight line.

Comparison GPS Suunto 9 and Polar Grit X

In the second arrow you can see that the Grit X repeats the mistake for which the Polar have been known... although it is true that in the Vantage M it is not appreciated at any time. By the way, I haven't mentioned it yet, but it seems that restoring the FR945 firmware solved the issues I was having with it. As I said, the tracks that were coming out from it were horrendous.

Let's go on... complicated place. Crossing the highway by a bridge over it, to which I reach at the a slow pace and I still don't want to go over zone 2. The result is that I go uphill even slower, making a 180 degree turn.

Comparison GPS Suunto 9 and Polar Grit X

The only watch that has correctly recorded the climb (which is on the side next to the parking lot) is the Garmin. The other three have diverted. Again on the descent is the Garmin that has been the most accurate, with the Vantage M and the Suunto 9 following closely. The Grit X has again made the descent knot with a displacement of a few meters.

But the Garmin has not always done the correct route, shortly after the descent of the bridge the Grit X and FR945 move towards the sidewalk on the left while the Vantage M and Suunto 9 making the correct route.

As you can see the Grit X is already dragging the error (and I don't want to be a broken record... but it's what I've been seeing in the Vantages for years), but the 945 is inexplicably shifted halfway and that's less common.

Comparison GPS Suunto 9 and Polar Grit X

It doesn't always have to be mistakes. There are also times when the four fully agree, which is what really has to happen.

Comparison GPS Suunto 9 and Polar Grit X

Test #2

Let's go to the second test. On this occasion I replace the Vantage M with the COROS APEX Pro, with GPS + GLONASS. A slightly faster workout than the previous one but also not lightning fast (5:50 min/km on average).

One of my usual routes, so I'm going to focus on the points I know are always more conflicting. To add details, this day was cloudy, making it more difficult to receive satellite signal (in test #1 it was completely sunny).

In the first image before we zoom in we can already see that there is something strange in the Suunto track... but we will get to that point later on.

Comparison GPS Suunto 9 and Polar Grit X

At the beginning of the route one thing that catches the eye is that the COROS happens to have a similar error to what suffered the Grit X in the first run. It goes into an error of 3-4 meters and keeps it. As I say it is not excessively important, because the distance and pace that you get will be the right ones, it's just that the track is off and you can see it on the map.

Comparison GPS Suunto 9 and Polar Grit X

Let's go to the first of the hotspots, a turn of about 100 degrees. The Polar Grit X (still in GPS+GLONASS) reaches that point with the same error we've been seeing so far, but it takes the corner correctly, as does the COROS and Garmin. But the Suunto cuts the corner by a few meters.

Comparison GPS Suunto 9 and Polar Grit X

That can be more problematic if it happens constantly, because in a long workout or marathon race, those two meters from here plus those two meters from there can end up accumulating a good hundred meters.

Next hotspot. Historically, the pass over the bridge and the turn after crossing it often creates problems. In this case, apart from more or less meters of displacement by almost evey watch (the COROS has the correct path), the turn is reasonably good, within the error of being a few meters off the actual route, especially noticeable in the case of Garmin and Grit X.

Comparison GPS Suunto 9 and Polar Grit X

This turn is usually very problematic, as two changes of direction are made in very little ground space. The COROS APEX Pro nails it, while the other three behave reasonably well, always considering that at the turning point they arrive slightly displaced.

Comparison GPS Suunto 9 and Polar Grit X

Further on Suunto starts to get lost. You can appreciate that while COROS, Garmin and Polar make the turn correctly and continue along the promenade route, Suunto makes a "bust" before the turn point and then takes a while to recover. That is, it has reached that turn point with not too many satellites for poder to get information from.

Comparison GPS Suunto 9 and Polar Grit X

But at the exit of Puerto Banus is where it loses it completely, which is what you saw in the first picture.

Comparison GPS Suunto 9 and Polar Grit X

This time the Suunto does not have much justification, because none of the other three watches present any problems.

The next point I like to observe is when crossing the road through a passage below the highway. At this point the watches lose the signal, because I spend several seconds under the road, and what interests me is to observe what is the behavior both inside the tunnel and the speed to recover the signal when leaving the tunnel.

Comparison GPS Suunto 9 and Polar Grit X

Suunto 9 takes the easy path and simply joins the point where it has lost the signal with which it has recovered (and took a little longer than the others). Remember what I just said in reference to continuously trimming corners? Well, we keep adding meters...

Meanwhile the Polar Grit X and the COROS APEX Pro make the stretch under the highway perfectly, identifying that we have run in that direction even when they were not receiving GPS signal. They make some strangers movements out of the tunnel, but it's totally normal considering the situation.

Garmin for its part is also lost quite similar to Suunto, although performing the recovery in the opposite direction.

Little more to stand out from this workout, beyond noting that sometimes there is separation of two tracks. The reason? I have the Grit X and FR945 on my left arm and hand, and the COROS and Suunto on my right arm and hand, so each tends to deviate slightly to that side.

Comparison GPS Suunto 9 and Polar Grit X

So just to be clear on which of the four was on the right path in this last image, it is the Grit X that shows the correct track in that section.

Bottom line

After these two tests I have been able to come to some conclusions which I will detail below:

  • Suunto 9: With the use of BeiDou satellites the performance is good, but not perfect. Especially in the second test it is where it has had the most notable failures. But remember, no matter how many updates the manufacturers make, a GPS watch is not a precision tool and will always be exposed to more or less important errors.
  • Polar Grit X: The initial result is not bad, but it strikes me a lot that with the two Polar at once, the one in GPS+GLONASS (the Grit X) has the offset and the one in GPS+Galileo (the Vantage M) does not. So the following tests that I do for the full review on the Polar Grit X will be performed with GPS + Galileo to see if the tracks improves. It is curious that the COROS has had similar behavior being also in GPS+GLONASS... It is possible that there is some specific situation with the Russian satellite system at the moment.
  • Garmin FR945: If you have problems with tracks or GPS reception of any watch... rule number 1: restore it back to stock. In the case of Garmin the improvement has been HUGE.

The full review on the Grit X will be published in about a couple weeks, so keep in mind if it's a model you're interested in to come back and check it out.

I hope you stay well, totally healthy and starting to recover your usual workouts. Thanks for reading!

Eduardo Mateos

I've been surrounded by electronic devices of all kinds for more than 25 years. Using them, testing them, taking them apart and dissecting them. Long distance triathlete: I swim, run and cycle for a long time. Maybe too much.

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  1. I have a Polar Vantage M, and in my area (center of Asturias) it works much better in GPS + Galileo, if it is in GPS + Glonass it tends to make more mistakes in tight turns, high buildings, etc. Obviously it is not perfect in any mode, but in general it improves a lot, and on trails it also works better with Galileo. Maybe something similar happens to the Grit X.

    Reading your article I understand perfectly what you say about the Vantage, in one of my most common routes I follow a road with wide curves for 2 kilometers, just at the beginning of the training, and it is usual to mark the track 1 or 2 meters from the sidewalk, but it does it constant during those 2 kilometers, therefore the pace and distance is marked correctly, and just when I make a 90 degree turn to cross a dam, that I leave that road, and it is the first abrupt change of "course", it happens to mark the perfect track from then on.

  2. As always and once again, thank you for your analysis.
    I've always been a Suunto, Ambit2s, Ambit3 Sport, 3 Peak, Spartan Ultra... 2 months ago I sold the Spartan and I've kept the Peak because it's the one that works best. All my team has Garmin and we do challenges and internal challenges as an incentive, and I'm considering taking a Fenix 5x Plus or a 945, but Suunto still attracts me a lot of attention, I really like the 9, but I'm really put off the experience with Spartan and the whole ecosystem of the web, the app's that now can not be installed on the watch or the App Suunto. I've been going for a while and I still don't know what to do?

  3. Thanks for the comparison! Very good test!
    Some instability, signal loss, clipping of curves, straight lines and wobbling are quite persistent problems in Suunto. They have not found a solution for years. Although it does not affect much the measured distance it is quite annoying for those of us who like precision. It was precisely the reason (among others) to switch from Suunto 9 to Coros. The Finnish has never been up to par with any Ambit Peak from its own house.
    In this regard: ...running slower GPS has a harder time? Or even walking. It is a myth that has always been transmitted by the Finnish brand. If a lie is repeated 1000 times it becomes a myth or a truth. Or both. I can not agree because I am in possession of a watch with Sony chipset and this does not affect the quality of the track in the slightest or in a practically inaperceivable way.
    On the other hand I would like to add that I have also noticed some typical errors of the ones you mention in your GLONASS analysis. BEIDOU does it better. I think we finally have a constellation that works very, very well. The GPS+BDS combination is very accurate and stable. I still don't know its direct impact on battery life.
    A salute.

  4. Great analysis. I can't wait to see the test of the grit x with galileo to see if the improvements are noticeable. And also to see it in the mountains that is focused for that purpose and to know how it responds to these new features it brings compared to other models. Greetings and thank you for these tests.

    1. Thank you Sergio.

      I am still working with him, the proof will be published in the next few weeks.

      As for the mountains it's not going to be easy given the difficulties we have right now. But come on, to test well proven Hill Splitter and FuelWise I don't need so much field either...

  5. Great analysis again Eduardo
    Like Sergio, I also await with great trepidation the full review of the Grit X-.
    I've had it for four days now and little by little I'm getting the hang of it.
    A hug.

  6. Hello, first of all thank you for your excellent work, no doubt that every time I buy something I use the blog link, what less.
    My question, taking advantage of the revisit to the Polar Grit... is it possible to configure the main screen of the polar to show the time of sunrise and sunset? I know it's a small thing, but on my garmin 920xt is something that I used a lot, especially to know at a glance if I had time to go out or I was going to the roller ... I've had garmin for a long time, both edge and forerunner, but I want to try something new and more "elegant" like Suunto 9 or Polar vantage v titan // Grit, so my diatribe depends on a factor so irrelevant to others like that.

    Thank you very much!

      1. Thank you very much for the quick answer... I'm going to read the whole review but without it... it's a small thing, yes, but I give it a lot of importance xD

        Maybe the choice is between a big and elegant suunto or a garmin... it remains to be seen.

        A salute!!!

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