GPS computer problem, Cycplus M1

pep.fermi
pep.fermi Posts: 383
edited April 28 in The cake stop

First ride with this device. Not happy.

I rode my usual session of short steep hill reps, done it zillions of times in the past with Smartphone and Strava and they always recorded 60km 2025m. These numbers consistent with the like of mapmyride etc.

Today Cycplus M1 recorded 48km 2120m. Never mind the climbing is more, could well be I did a couple of hills more, not sure, but if so the distance should be 60+2km, not 48km.

My guess is when I ride below a certain speed it simply record zero. These hills average 10% so I was overall very slow and at the steepest points extremely slow. In fact, very often I was shown current speed 0km/h. But whatever, I want the total distance to be correct.

Not happy.

Anyone has relevant experience, with this or another GPS device?

Comment?

Thanks,

Comments

  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,061

    Have you tried "correct distance" and "correct elevation" on the Strava website (app doesn't have distance option iirc)?

    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • pep.fermi
    pep.fermi Posts: 383
    edited April 28

    No, I haven't. Not yet. I was not aware there is such a feature on Strava. I will try it now.

    But still, on this particular route I know the distance. What when I ride a "new" route...?

  • pep.fermi
    pep.fermi Posts: 383

    OK, I have adjusted the climbing on Strava.

    But the distance is wrong ca 20%😱

    And of course I'd like it to be correct at first.

  • briantrumpet
    briantrumpet Posts: 20,518

    Might be a silly question, but have you made sure that the firmware is the latest version? My Xoss wasn't happy until I'd done that, and it looks to be a similar sort of budget GPS.

  • pep.fermi
    pep.fermi Posts: 383
    edited April 28

    @N0bodyOfTheGoat

    OK, I went back to Strava and I "corrected" both distance and climbing to GPS-based data, rather than device based data. New numbers are 55km 2110m ( I expected 62km 2110), old numbers 48km 2120.

    Thanks so much for the feedback.

    @briantrumpet thanks for mentioning updating the firmware, no I had not thought about it. I checked it up and it says it's up to date. Still good suggestion though.


    If at all anyone interested, here the ride

  • pangolin
    pangolin Posts: 6,653

    This hill you go up and down approx 36 times is intersting. Is it actually the same path you take each time? There's a lot of variance in the route. This is also shown pretty clearly at the top where the track is several meters off of being on kosterbergstasse. That will add up to a fair difference over the ride.




    - Genesis Croix de Fer
    - Dolan Tuono
  • pep.fermi
    pep.fermi Posts: 383

    @pangolin

    This is the riding I do because I'm obsessed with mountains, and climbing, and I live in flatland. So I ride many times the "biggest" hill in the area. Which apart from being the biggest is the only one, and it's miniscule.

    It's one road, so one can't really take different routes. The variations you see must be fluctuations in the measurements..

    Back to the GPS device: as I wrote: I rode this identical session dozens of times in the past, with smartphone and Strava, and the despite similar variations in the followed route, the total distance and total climbing numbers never really changed from time to time. That's why I came to "blame" the device.

    I read on Strava the explanation on the difference between "device based" and "GPS based". It explains a lot.

  • briantrumpet
    briantrumpet Posts: 20,518
    edited April 28

    That trace does look extremely approximate... even with my cheap GPS Xoss, it's never out by more than a couple of metres, to the extent that you can easily see when I've stopped at a gateway to, erm, 'admire the view'.

  • pblakeney
    pblakeney Posts: 27,382

    Is this a prime example of "buy cheap, buy twice"?

    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • briantrumpet
    briantrumpet Posts: 20,518


    Well, with my Xoss, yes: I bought one as it was cheaper than a wireless non-GPS Cateye. I liked it enough that I bought another one to leave in France. The app's a bit buggy, but once traces are uploaded synchs fine with Strava. Since all I use it for is tracking rides for my own records, it's perfectly acceptable.

  • pep.fermi
    pep.fermi Posts: 383

    The road is very narrow. So I think the measurements is not bad. Beside, as I wrote: I rode this zillions of times, with Strava and smartphone, and the trace never really looked different than today with a cycling device.

  • pangolin
    pangolin Posts: 6,653

    I disagree, there are several tracks up/down that are closer to the roads either side of the one you were on.

    Was your phone+Strava combo really as approximate to look at?

    - Genesis Croix de Fer
    - Dolan Tuono
  • pep.fermi
    pep.fermi Posts: 383

    @pangolin I was about to reply you're wrong but I checked better and it seems you're actually right.

    Here my last ride with phone + Strava, the route is much closer to the road (= the only road I always follow), the new device seems indeed less precise.

  • pangolin
    pangolin Posts: 6,653

    Yeah that makes sense, add that up over the whole ride and there's your difference.

    If you still can I'd return it.

    - Genesis Croix de Fer
    - Dolan Tuono
  • briantrumpet
    briantrumpet Posts: 20,518

    And that trace is good evidence of its inaccuracy for justifying its return.

    I've Googled 'GPS inaccuracy' for this model, and can't find any particular trend, so maybe it's just a faulty unit.

  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,061

    As regards GPS accuracy, might be worth checking if their is a setting that alters the polling frequency.

    On my Lezyne GPS units, by default they use "adaptive" rather than "1 sec," supposedly increasing battery life per charge at the cost of accuracy. https://support.lezyne.com/hc/en-us/articles/360004872913-Settings-Adaptive-Recording

    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • pep.fermi
    pep.fermi Posts: 383

    @N0bodyOfTheGoat

    good point, thanks, I had not thought about it.

    But no, I just googled it and I don't think there is such a settings.

  • pep.fermi
    pep.fermi Posts: 383
    edited May 9

    Today's ride with two devices, here the two measurements:

    Smartphone + Strava: 74km 2653m

    Cycplus M1: 63km 3012m

    I didn't expect such large discrepancies.

    Comments?

  • pangolin
    pangolin Posts: 6,653

    You know it's not accurate, why haven't you returned it?

    - Genesis Croix de Fer
    - Dolan Tuono
  • Pross
    Pross Posts: 43,479

    Yep, looks like it's conclusively faulty.

    It won't be much help but whilst I'm not a brand fanatic with things like GPS computers / watches I would always stick with a recognised brand unless it had multiple rave reviews.

  • pep.fermi
    pep.fermi Posts: 383

    Good question. I prefer to keep it because

    1) despite it being wrong, it is consistent

    2) it shows current elevation gain, correct me if I'm wrong but I think it's the only one that does it...

    3) largest display of all Cyclocomputers


    I paid 20eur for it and I'm still happy to have this rather than any pricier other.

  • Pross
    Pross Posts: 43,479

    I think Pangolin was suggesting returning it as faulty in exchange for one that works properly. Keeping it because it is consistently wrong doesn’t feel like a good reason to be honest.

  • pblakeney
    pblakeney Posts: 27,382

    In my opinion incorrect data is worse than no data.

    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.