Garmin Edge 500 and a turbo trainer.

Inutero
Inutero Posts: 111
edited September 2013 in Road general
Just hooked my bike up to a newly bought turbo trainer. Does anyone know why mine won't show speed on it? Seems to sit at either 0 or about 2mph while i'm spinning away. It's defintley detected it :(

Comments

  • bigpikle
    bigpikle Posts: 1,690
    have you got a separate Garmin speed sensor on the bike that works on wheel speed? If not you wont get speed as the 500 uses GPS to work out your speed and obviously you're not moving....
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  • As above.... and have you turned off GPS on the unit?
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  • Inutero
    Inutero Posts: 111
    Didn't realise speed worked on GPS. I'd already turned the GPS off when i set it up.

    I have the cadence sensor on it too, which is working fine.

    Cheers guys. :D
  • So you have the speed sensor and the magnet on the spokes, but is the sensor picking up the magnet. You may need to move the magnet/sensor so they work together. Have you set wheel size?

    And turn GPS off for Turbo.
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  • Inutero
    Inutero Posts: 111
    Sorted it :) . Don't know why but the arm on the cadence sensor was about an inch away from the wheel magnet. I was only out on a ride yesterday and it was working as usual and i'm sure that there was never that gap. Must have twisted the sensor away from the wheel. Anyway, got it back to where it should have been and it's working a treat now :mrgreen:
  • hatch87
    hatch87 Posts: 352
    Inutero wrote:
    Sorted it :) . Don't know why but the arm on the cadence sensor was about an inch away from the wheel magnet. I was only out on a ride yesterday and it was working as usual and i'm sure that there was never that gap. Must have twisted the sensor away from the wheel. Anyway, got it back to where it should have been and it's working a treat now :mrgreen:

    You probably wouldn't of noticed, the GPS would of just taken over and still given you a speed, it might not of ever been set up right :D
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  • slowbike
    slowbike Posts: 8,498
    Why do you need to turn GPS off? I've never bothered with a 705 or 800 - don't even know how too ... it just picks up the speed from the speed/cadence sensor ...
  • Mikey23
    Mikey23 Posts: 5,306
    So when you have a speed cadence sensor on and use the bike outside, does it automatically default to the speed sensor or the gps? Or am I supposed to configure something on the 500
  • When you switch the garmin on it usually says 'speed/cadence detected'
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  • If I remember correctly, when you next switch on the 500 (having previously disabled the GPS for a turbo session), it defaults to the GPS being enabled.
  • apreading
    apreading Posts: 4,535
    As I understand it, when you are outside, the unit calibrates the size of wheel/tyre by measuring over a set distance as measured by GPS and then uses the speed sensor with the magnet on the wheel (pednatic here - it isnt the cadence sensor in respect of speed/distance travelled although the two are combined in one unit) from there on.

    Whether it does the calibration once, when you first install the speed sensor or repeats this every rider, I am not sure. Ideally it does it every ride as you may change wheels/tyres and therefore circumference. And how clever it is - whether it just measures the first 200m/first mile or whether it looks for a straight bit with little altitude change, I have no idea. Supposed to be more accurate than the GPS once calculated though...
  • Mikey23
    Mikey23 Posts: 5,306
    Yes I did get some message about calibration when I was out yesterday but it disappeared before I could read it. Which prompted my question as I've had to manually disable gps for the last three weeks of riding indoors...
  • ddraver
    ddraver Posts: 26,391
    I'm 90% sure my edge 800 picks up the speed from the sensor, I only really turn the GPS off as it stops it from trying to plot the "route" when I upload to Garmin Connect...
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  • On my edge 510 is automatically picks up my speed off the wheel rather than GPS. I don't have to change any settings.
  • Slowbike wrote:
    Why do you need to turn GPS off? I've never bothered with a 705 or 800 - don't even know how too ... it just picks up the speed from the speed/cadence sensor ...

    If I leave the GPS on for my 800 when using the Turbo, it keeps trying to find satellites which is annoying and distracting

    When uploading the session data to Ascent (ride logging program for Mac), then the 'track' of the ride is a jumble of lines all over the place with altitude data all over the place. It's just messy and doesn't contribute anything.

    Re : the wheel sensor, if the unit is set to auto it will calculate wheel/tyre size via GPS, speed and, I think, cadence sensors, every time you ride. This too can get annoying. If you set the wheel/tyre size it keeps this info and uses it to get more accurate speed/distance readings.
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  • slowbike
    slowbike Posts: 8,498
    Slowbike wrote:
    Why do you need to turn GPS off? I've never bothered with a 705 or 800 - don't even know how too ... it just picks up the speed from the speed/cadence sensor ...

    If I leave the GPS on for my 800 when using the Turbo, it keeps trying to find satellites which is annoying and distracting
    Ah - my turbo is in the conservatory - no issues with finding satellites!
    When uploading the session data to Ascent (ride logging program for Mac), then the 'track' of the ride is a jumble of lines all over the place with altitude data all over the place. It's just messy and doesn't contribute anything.
    I upload to garmin connect and strava - I'm really not bothered about the track.
    Re : the wheel sensor, if the unit is set to auto it will calculate wheel/tyre size via GPS, speed and, I think, cadence sensors, every time you ride. This too can get annoying. If you set the wheel/tyre size it keeps this info and uses it to get more accurate speed/distance readings.
    Mine has only ever noticeably calculated once - so I'm assuming it only does it once or on demand. Thinking about it - if it did update automatically every time then when I swap wheels with on my CX (cx or road slicks) then I should get an update notice. I haven't had one ... Ultimate would be to check the registered size, swap wheels, ride and then check registered size again.
  • I have my 800 set with two bike profiles, road and mtb, so two different sizes. I ride each bike practically ever other day, so the calibrating may have been due to that.
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  • Mikey23
    Mikey23 Posts: 5,306
    Looking at my latest strava traces, the speed and distance lines seem to be a lot more regular so I think it's feeding off device and not the gps which is cool... Thanks for your input guys
  • buckles
    buckles Posts: 694
    I wish it would ask whether to switch GPS on every time it's switched on, rather than defaulting to GPS on.
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