Wrong calculation of actual Pace — TomTom Community

Wrong calculation of actual Pace

JusoJuso Posts: 3 [Apprentice Traveler]
I am running. Now the downhill area comes. I run at about 4:30 pace, which is announced every kilometer on the watches and I can also see it when I download data to PC.
But while running, actual pace is showing values higher than 4:30 all the time (sometime even 5:30 without me slowing down), which is of course wrong (average can't be less than the the lowest value).
This I can confirm after exporting the data to MS Excel. One line per second. There are times from about 4:35 to almost 6:00 for each second in that kilometer. But no one under 4:30.
When I calculate the average pace from distance and time for this one kilometer (from data exported), it is 4:27, which is exactly the value shown on MySports and also in the watches for that one kilometer.
Conclusion - actual pace calculated in the watches and displayed during the run (in the bottom left corner) is completely wrong.
This can also be seen in the screenshot (attached) on highlighted kilometer.
What to do with that?
I can upload exported data from watches to confirm my observations.
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Comments

  • tfarabaughtfarabaugh Posts: 15,815 Superusers
    Juso wrote:
    I am running. Now the downhill area comes. I run at about 4:30 pace, which is announced every kilometer on the watches and I can also see it when I download data to PC.
    But while running, actual pace is showing values higher than 4:30 all the time (sometime even 5:30 without me slowing down), which is of course wrong (average can't be less than the the lowest value).
    This I can confirm after exporting the data to MS Excel. One line per second. There are times from about 4:35 to almost 6:00 for each second in that kilometer. But no one under 4:30.
    When I calculate the average pace from distance and time for this one kilometer (from data exported), it is 4:27, which is exactly the value shown on MySports and also in the watches for that one kilometer.
    Conclusion - actual pace calculated in the watches and displayed during the run (in the bottom left corner) is completely wrong.
    This can also be seen in the screenshot (attached) on highlighted kilometer.
    What to do with that?
    I can upload exported data from watches to confirm my observations.

    The nature of consumer grade GPS is that each data point collected is only accurate to within 15m-30m of your actual location. We give it a lot more credit than it deserves, it is not exact, it is an estimate. The watch collects the data points and then tries to figure out a route using them (considering that some points may overlap or duplicate) and a corresponding speed. The watch then smoothes the data to come up with the most reasonable route taken according to the algorithm it is programmed with. This is why every watch, even two of the same model, will come up with different distances and speeds, as they are collecting different GPS data. And even though you are running steadily the GPS points are bouncing all around you so it thinks your pace is changing. For example if one GPS point is actually 20m behind you and the next one (collected a second later) is 20m in front of you, it is going to think you sped up to close the gap. In the same way if you reverse this it will think you slowed down. The smoothing algorithms attempt to clear up as much of this as possible but it is not an exact science.

    In addition, no watch has true "instant pace". It is all computed in arrears and is a balance between responsiveness and smoothness. A longer lag time gives you smoother data but is slow to react. A short lag time gets faster responsiveness but choppier data. TomTom is slow to react to changes in pace because it applies a long smoothing period to produce smooth, non-choppy data. If you are running at a fairly steady pace you will not notice the lag. However, if you are doing intervals or sprints or changing speed a lot the lag can be become more apparent. This has been a complaint since the first version of the watch was released 3+ years ago and really has not changed much, so I would not expect much to change now.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
  • JusoJuso Posts: 3 [Apprentice Traveler]
    All of this information I already read in the forum. I understood that it doesn't show right numbers, which I am not OK with as I previously had Garmin device which was able to show good results.
    But this behavior is different.
    What you say is that
    1 - due to GPS not being accurate it can't calculate right.
    2 - Spark calculates actual pace using smoothing algorithm and takes average for longer period
    This can't be true, because:
    1 - Placing exported data over the satellite map shows good accuracy. The overall calculated pace is OK. That means data measured are OK which I can also see in the log.
    2 - I would understand lag in changing the pace. I would also understand pace oscillating around real pace. What I don't understand is showing pace lower by about 0:20 - 1:20 constantly.
    This behavior is not a "bit" off-track, it is completely WRONG.
    The developers must be sabotaging the whole company and wanting all customers to go to competitors.
    For calculating an average from good data (which are apparently measured and stored), grammar school education must be sufficient.
  • ChavenChaven Posts: 17 [Legendary Explorer]
    I've had my Runner 2 cardio for just over a week now. Most of my training has been on a synthetic track which has given me an opportunity to do some reliable calculations.

    Firstly GPS integrated distances can be off by around 20 m over 400m. This appears to be fairly consistent. The worst I've seen is 70 m but this was on an overcast day. Distances are approximated by connecting several lines from start to end of your run. Around bends the distance measurement gets worse the faster you are moving. If it takes me 3:15 to walk one lap and if the measured GPS distance is 420 m. Then the error in average pace would be around 4.76 % or around 23 secs.

    I would never place my money on instantaneous pace readings on non linear paths considering the limitation of GPS accuracy.
  • JusoJuso Posts: 3 [Apprentice Traveler]
    I agree with you. Under these conditions I could accept some tolerance.
    Where I can't is when the distance and time is measured OK (which I can see in exported data) but the calculated values (pace and speed) is way wrong. It even doesn't oscillate around correct value but it is shifted to one side (slower one).
    That means math was not understood by developers.
    And surprisingly, my previous old Garmin ForeRunner 205 was able to show relevant data.
  • Timoter1996Timoter1996 Posts: 4 [Apprentice Traveler]
    I've the same problem. Tomtom has to find a solution for this. It is a big big problem when accelerating much within the training (for example intervaltraining). The pace on the watch is adjusting really really slow. which results in an pace which is correct AT THE END of the interval. What we need is an pace DURING the interval.
    After the interval when slowing down its also indicates an really really high speed for about 40 seconds. SO when accelerating to an higher speed it keeps indicating slow. And when slowing down it indicates an speed which is too high.
    I bought this watch because I want to know my actual speed when running. With actual speed i mean:
  • Timoter1996Timoter1996 Posts: 4 [Apprentice Traveler]
    Addition: just de-smooth the algorithms
  • ShbshbShbshb Posts: 2 [Apprentice Traveler]
    Same problem! For the Entire run the average pace is going down slowly and steadily- negative splits! But the current Pace is reading significantly higher than the actual pace almost the entire time. How can average be dropping when current pace is higher?

    If algorithm is smoothing, then it ought to be accurate or below average sometimes. I know what 7:45 pace feels like. Running 7:45 for an entire mile confirmed by partners Garmin and Tom Tom pace is reading 8:10 the whole mile.

    After exporting, all the splits look perfect! Exactly what the run felt like and confirmed by partners garmin.

    How could Pace be displaying 20-30 second slower almost the entire run.

    Ready to return Spark 3.
  • ShbshbShbshb Posts: 2 [Apprentice Traveler]
    Mistake in my 3rd sentence. WROTE: But the current Pace is reading significantly higher than the actual pace almost the entire time. MEANT TO WRITE: But the current Pace is reading significantly higher than the AVERAGE pace almost the entire time.
  • tt_gttt_gt Posts: 260 Retired Community Managers and Staff
    If you are finding the current pace is not working so well for you, there are other approaches you could try:

    - If you have a spark/runner 2 or later, you can use the splits setting which will alert you every mile/km with your pace averaged over that last mile/km
    - on all watches, you can set yourself using lap training. You can configure laps to any distance or time, and use the 'lap pace' screen to show your pace averaged over the current lap. Additionally, the watch will also alert you when you change laps, again giving you the total pace that you averaged over the previous lap. Vary the length of the lap to make the output more or less smoothed / responsive.
    - one final approach which I find useful if trying to run at a constant speed, would be to use race training mode, and set up a custom race at your desired pace. The watch will then show you constant feedback of whether you are gaining or falling behind that pace.
  • starfleetyajstarfleetyaj Posts: 42 [Legendary Explorer]
    I've found that most of the "pace" screens (and even the data points on MySports) to be wildly inaccurate in realtime. However, both manual and autolap functions show an average pace for the lap on the splash screen which seems fairly dead on. I've used this for splits down to a quarter of a mile.
  • Timoter1996Timoter1996 Posts: 4 [Apprentice Traveler]
    Tomtom does not understand the problem:

    Tomtom watch indicates speed differences too slow. 5:30 min/km ---> 4min/km takes about 1 minute on the watch (so when it is actually showing the right pace). This is a problem while doing intervalruns, because I can't see the right speed during my interval. Changing the lap distance does not change how fast tomtom watches recognise accelerations.

    add: I can see afterwards on strava the correct data (I can actually see that I accelerated from 5:40 ---> 4:00 min/km). This means that the data is OK. BUT it doesnt show the 'OK' data during my run.

    all in all: afterwards right data (only on strava). During the run wrong data...

    please fix this problem in the next update !
  • tfarabaughtfarabaugh Posts: 15,815 Superusers
    Tomtom does not understand the problem:

    Tomtom watch indicates speed differences too slow. 5:30 min/km ---> 4min/km takes about 1 minute on the watch (so when it is actually showing the right pace). This is a problem while doing intervalruns, because I can't see the right speed during my interval. Changing the lap distance does not change how fast tomtom watches recognise accelerations.

    add: I can see afterwards on strava the correct data (I can actually see that I accelerated from 5:40 ---> 4:00 min/km). This means that the data is OK. BUT it doesnt show the 'OK' data during my run.

    all in all: afterwards right data (only on strava). During the run wrong data...

    please fix this problem in the next update !

    They actually updated this in the Fall and it improved a bit, but clearly not enough for everyone. I doubt you are going to see a change here, after all it has been this way for 3+ years. Unfortunately it is not as simple a taking distance/time, there is complex calculation involving satellite drift and ephemeral data and a bunch of other technical stuff that is over my head. I am not sure why some watches do it better than others, but it is not like Garmin is going to give their code to TT so I assume they are doing the best they can.
  • MarijeSiemannMarijeSiemann Posts: 3 [Neophyte Traveler]
    I've encountered this problem as well. I've just bought a Runner 2 Cardio, and during running, the current pace is completely off. Using the CSV data, I've calculated a moving average myself. See the graph. I've contacted TomTom about this and I hope they will respond to this.
    However, during cycling (last image), the speed seems to be OK. It seems to me that TomTom has tried to develop an innovative smoothing algorithm for the current pace/speed during running, but it is flawed. During cycling, it seems to be a simple moving average, working fine.

    I'm considering to use the 'cycling' activity for running. I'm going to test that soon.

    Running 1: bc36e233-3647-4cb0-a30a-8cc52acb7a6f.png

    Running 2: 186dca62-e7d7-4388-99ed-a3f3b04e6253.png

    Cycling: 22b64601-8dc7-4e49-8026-8450ffd253fc.png
  • PetervanderMeerPetervanderMeer Posts: 3 [Apprentice Traveler]
    For me the same story. During my first run with the new TomTom Runner 3 I encountered that the pace was not accurate. It really suprieses me that TomTom, a company that I know for accurate navigation software, is not able to program their running algortihmes this bad.

    Im quite a fanatic enthousiast runner that wants to improve my runinng times over and over. Therefore I need accurate pace in combination with hart rates and accurate distance. Now, this is impossible with this newest version of the TomTom Runner 3.

    TomTom, can you please comment on this that you at least understand the problem and commit you are facing a problem with this accurate pace.
    The workarounds mentioned everywehere in fora (like using the cycling mode, or deal with lag, or use the interval manual rounds mode) are not the solution.
    Please indicate if you are working on this, so I know whether to sell this new watch, because it can not be used by medium-professional runners.
  • Nomis89Nomis89 Posts: 1 [Apprentice Traveler]
    I've had the same problem too. Running at a continuous pace seems to be fine. With interval training it's just awful. My average pace off a session will be higher then then my maximum pace.
    Take a look at session 3.
    Then highest pace registered was 5:04min/km.
    The average pace of the session was 4:28 min/km
    and the max pace of the entire training was 4:31 min/km which it registered after i already slowed down.

    This is not a mistake, this a a major f up.

    When exporting it to strava it shows me data which is very accurate.
  • GobaterGobater Posts: 4 [Master Traveler]
    Hi,

    I have a Runner 3 updated to the latest Software and I can confirm this issue. It is very annoying. The Training Zone(Pace) is completely unuseful with the algorithm implemented in the watch. It is very hard to work in the zone. The resulta of the algorithm start to get close to the expected results after 6-8 km.

    I never get data values lower than my average pace / last km pace.

    It is understandable that GPS accuracy does not help, but cannot understand why this cannot be solved. The only solution I found is using laps training...

    Please fix! I would like to be able to use intervals!!
  • lajuleclajulec Posts: 1 [Apprentice Traveler]
    I agree wth these comments. My watch was accurate for a while, and now it has been wrong for the past 2 months. The ongoing pace does not fluctuate if you do intervalls. My old Garmin 305 was doing a much better job. Can this problem be fixed by the company?
    I will certainly not buy a tomtom product again unless they resolve this problem with my tomtom watch.
  • VickerspVickersp Posts: 1 [Apprentice Traveler]
    Same for me, just bought a Runner3 having previously owned a Multisport cardio. Current pace when running is terrible and means you can't use Intervals. Going to try what someone else posted and use the cycling function, it seems there may be an error
    on the running algorithm.

    I can send mine back to amazon though as I have just purchased and will not buy another TomTom at this rate!
  • kent davieskent davies Posts: 91 [Supreme Trailblazer]
    I've tried all the solutions provide and none of them worked. Instant pace and any feature that relies on it, is something that we cannot use.
  • 010runner010runner Posts: 17 [Outstanding Wayfarer]
    sorry just read that we should group all posts with the subject "pace" here. Can anyone actually confirm that they have a watch that does give the accurate current pace ? Though there are more complains it is not a massive problem it seems. That makes we wonder if there are different qualities, you know like cars, it happened you bought a monday morning car. To me it is unimaginable that a worldwide represented company litk TT would offer,sell,provide a watch that simply does not work for what it is meant. Reading back some posts this problem is inherited, the previous series 2 had it already. Or is it that a certain percentage of the production is affected?
    What is a better alternative for the T T spark 3 ?
  • MuffonMuffon Posts: 6 [Master Explorer]
    Same problem here. I think it's a dangerous feature. The watches make you think that you are running slower but you make higher effort to keep higher pace while your heart is freneticaly beating.
  • kent davieskent davies Posts: 91 [Supreme Trailblazer]
    @Muffon

    You are right. That's the biggest problem with the huge lag on instant pace. You are told that you are at a slower pace (when in fact your pace is quicker) and you automatically tend to push harder to hit the desired target pace. That makes you spend more energy and your heart starts beating at a higher rate thus, you will probably get tired quicker than you should. If you do training based on pace, this is definitely not the watch to use.

    Discloser here. For what I've read, other watches normally struggle with this but they tend to update the instant pace more rapidly than TomTom.
  • UsedtobeadistancerunnerUsedtobeadistancerunner Posts: 1 [Apprentice Traveler]
    My TomTom runner used to give really good pace times, but something changed in October/November 2016 and now I have the same problem that everyone else is reporting. You just have to look at the graphs on my training races to to see the dramatic change. Come on TomTom, it's about time you fixed this.
  • AthloniAthloni Posts: 15 [Legendary Explorer]
    Everybody at TomTom knows It's a well known bug on all TomTom watches. They calculate it to smoothen out the peaks, but the calculation is far to aggressive. The only problem is, that nobody at TomTom realy cares :(
  • Tiago MirandaTiago Miranda Posts: 10 [Master Explorer]
    Why Tomtom does not give us any feedback about this issue?
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