Losing distance with the Edge 800

moscowflyer
moscowflyer Posts: 540
edited October 2012 in Road general
I've had this issue three times now but with two different 800 devices. Along a 10 mile route into work I'm losing distance. It's a 10.2 mile stretch and today it's only calculated 9.2 miles, this has happened once before on the same route and on another shorter route where I managed to lose nearly half a mile in a 3.5 mile stretch.

Satellite signals are fine, it's a wide open space (I'm losing this distance going down the Portsmouth Road between the Scilly Isles and Kingston). Anyone had any issues like this before? It never happened once when using my Forerunner 610 or the previous 305, which I was using for 18 months before buying the Edge.

Could it have anything to do with the magnet on the wheel? I thought this was for the cadence sensor but it seems it may override the GPS signal for speed/distance? It has only happened on the bike with the magnet on.

Comments

  • moscowflyer
    moscowflyer Posts: 540
    Hmmm, I think I've answered my own question there haven't I?
  • DevonClimber
    DevonClimber Posts: 90
    MoscowFlyer wrote:
    Hmmm, I think I've answered my own question there haven't I?

    Think you may have, always good to ask though. :)
    “If you do what always do, you'll get what you always get.”
  • amaferanga
    amaferanga Posts: 6,789
    Do you have wheel size set to auto or custom? I suspect it's auto and the dodgy distance is due to incorrect calculation of the wheel size. So change it to custom and either measure the circumference of the wheel or use one of the tables that provide approximate (but IME perfectly good) calues.
    More problems but still living....
  • moscowflyer
    moscowflyer Posts: 540
    amaferanga wrote:
    Do you have wheel size set to auto or custom? I suspect it's auto and the dodgy distance is due to incorrect calculation of the wheel size. So change it to custom and either measure the circumference of the wheel or use one of the tables that provide approximate (but IME perfectly good) calues.

    Custom, but I've just removed the magnet anyway now. I've never had any issues with calculations using just the GPS on the other bike, so don't see the need to use the magnet for this one really.
  • antfly
    antfly Posts: 3,276
    It's more likely that there was too big a gap between the sensor and the magnet so it was missing bits out, auto is always pretty accurate. One area where the magnet is better is recording max speeds when going downhill fast, GPS can be way out.
    Smarter than the average bear.

Categories