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Discrepancies between Cyclemeter and Strava Distances

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  • December 14, 2014 at 10:18 am #22858
    penguin116

    Apologies if this has already been covered elsewhere, but I’m really struggling with this.

    I have been using Cyclemeter (Elite version) on my iPhone to record my rides for a few months now, then uploading them to Strava once I’ve got back home. I then noticed a couple of weeks ago that the distance covered according to cyclemeter was significantly higher than on Strava once I’d uploaded it. For instance, yesterday, I went for a short 16-mile spin. At the end of the ride, cyclemeter reckoned I’d covered a smidge over 20 miles, and when I uploaded it to Strava it said I’d covered 16.3 miles.

    I presume that cyclemeter is using the input from my speed sensor rather than the GPS of my iPhone. I’ve got a Panobike Cadence and Speed sensor on the bike, and I’ve put in my wheel circumference into cyclemeter (2099mm) which I’m pretty sure is correct – 700c rims with 622-23c tires. I don’t think that there’s any other settings that need to be configured.

    When I look at the detail of my speed during the ride on cyclemeter, I top out at 40mph (which I think is frankly unrealistic) and on Strava it says it’s about 33mph (which seems a lot closer to the truth 🙂 although I suppose I could be doing myself a disservice 😀 ).

    So I’m confused as to what’s going wrong here. Any help would be much appreciated.

    Thanks

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Viewing 12 replies - 16 through 27 (of 27 total)
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  • December 16, 2014 at 10:01 am #823379
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    TimC340

    Speed/cadence sensors aren’t
    Speed/cadence sensors aren’t particularly accurate devices; they’re simple magnetic switches which can have errors from all sorts of reasons – wrong gap. too wet, battery expired (causing transmission errors to the head unit), etc. Strava will ignore the part of the .tcx file including the speed sensor info, and in this case will use the far more accurate GPS info. Not that GPS is infallible – and GPS altitude information from cheap receivers such as those on bikes is very poor.

    The Bryton/Strava rollers session problem is a pain – I agree that if you’ve done an hour at FTP you should be able to analyse all the data, including speed and thus distance. I use a Garmin head, upload to Connect which then distributes to Strava. Alternatively, I use TrainerRoads (via an ANT+ USB dongle into the ‘puter), download the session and then upload it to Strava. Either way seems to work ok.

    December 16, 2014 at 9:43 am #823377
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    andyp

    le Bidon wrote:turbo sessions

    le Bidon wrote:
    turbo sessions shouldn’t contribute to your yearly total! ;)

    This is quite literally the strangest cycling ‘rule’ of all time. Freewheeling down a big hill counts towards your yearly total, but an hour at FTP doesn’t?

    December 16, 2014 at 9:41 am #823375
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    le Bidon

    Seems that even Strava knows
    Seems that even Strava knows that turbo sessions shouldn’t contribute to your yearly total! 😉

    December 15, 2014 at 9:30 pm #823373
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    stealth

    I uploaded my Bryton onto
    I uploaded my Bryton onto Strava yesterday & my 36.7mile turbo session from yesterday morning turned into a 0.3km ride at 0.2km/h average.

    December 15, 2014 at 2:50 pm #823371
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    penguin116

    I got a response back from
    I got a response back from Abvio. They said…

    Thanks for writing to us about your Cyclemeter vs Strava stats. I’m glad to help and I have a 2-part answer for you.

    — The discrepancies you are seeing are not uncommon. When you send your Cyclemeter data to Strava, they read in our data but then they use their own algorithms to calculate the values for things like distance, speed, stopped time and moving time. As a matter of fact, if you are using a speed sensor with Cyclemeter to determine your distance and speed, those values are not used at all by Strava. Instead, they use only your GPS data to come up with your distance and speed. So, again, seeing differences is not only usual, it’s to be expected.

    — We don’t have a Panobike Speed and Cadence Sensor in-house, so we haven’t tested it ourselves. However, we have
    had multiple customers write in with problems because the sensor was generating exceptionally high, invalid speeds. That’s why we haven’t added it to our official list of supported devices. Here’s a page on our website with a list of devices that we do support:

    https://abvio.com/question/devices/

    Sorry I have answers – but no solutions. When/if you are in the market for a new speed/cadence sensor, we recommend Wahoo. We work very closely with them and our apps are designed to work with their products. However, there are other sensors that also will work well and you can check them out on our web page.

    So this all suggests the inaccuracies are in using the Panobike speed and cadence sensor – anyone else had any problems with this?

    December 15, 2014 at 12:42 pm #823369
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    gdmor10

    from what I understand GPS
    from what I understand GPS doesn’t do altitude very well, I remember being out sailing once and the GPS on the yacht said we were 3m below sea level – am pretty sure that was not correct.

    December 15, 2014 at 8:08 am #823367
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    penguin116

    Yes. I agree.
    I’ve noticed
    Yes. I agree. 🙂

    I’ve noticed on a couple of other forums that others are also seeing similar discrepancies not just with Cyclemeter, but a variety of different apps that do the same thing. The general suggestion is that it’s due to inaccuracies in the GPS module of the smartphone (doesn’t seem to matter if it’s iOS or Android). I’m not convinced though – I’m still pretty sure it’s something to do with the speed sensor taking precedence.

    I have emailed Abvio support to see if they can shed any light on the issue, but as yet I’ve not heard anything in repsonse.

    December 14, 2014 at 11:18 pm #823365
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    Man of Lard

    You’d like to think so… But
    You’d like to think so… But logic goes out of the window when anything to do with computers is involved 🙂

    December 14, 2014 at 10:53 pm #823363
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    penguin116

    Man of Lard wrote:Have you

    Man of Lard wrote:
    Have you allowed the real GPS position on your iDevice? If you don’t then the route it plots will be based on cell tower info and in a rural area that can be miles wrong (positionally)

    Ok. I’ve got that. It’s all correct for Strava. Cyclemeter doesn’t appear in the list, though. The general setting for Background App Refresh is enabled, so presumably if an app doesn’t have a specific setting, the general setting would take effect.

    December 14, 2014 at 9:37 pm #823361
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    Man of Lard

    OnTheRopes wrote:I cannot

    OnTheRopes wrote:
    I cannot speak for Cyclemeter but when I have used the Strava App on my phone and also uploaded to Strava from the Garmin there has always been a big discrepency in altitude. I mean a BIG discrepancy like up to twice the amount on occasion. No idea why.

    Because they use different criteria to decide what is a real altitude change (and what is GPS calculation error)

    December 14, 2014 at 9:36 pm #823359
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    Man of Lard

    Have you allowed the real GPS
    Have you allowed the real GPS position on your iDevice? If you don’t then the route it plots will be based on cell tower info and in a rural area that can be miles wrong (positionally)

    https://strava.zendesk.com/entries/22533685-Strava-iPhone-app-and-new-iOS-7-settings (this for the settings you need to look at)

    December 14, 2014 at 5:37 pm #823357
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    OnTheRopes

    I cannot speak for Cyclemeter
    I cannot speak for Cyclemeter but when I have used the Strava App on my phone and also uploaded to Strava from the Garmin there has always been a big discrepency in altitude. I mean a BIG discrepancy like up to twice the amount on occasion. No idea why.

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