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Edge 25 & Speed/Cadence Sensors

chenks76
over 7 years ago
Hi, just got an Edge 25 and the "Bike speed sensor and cadence sensor" kit.
got it all installed and the edge detects both devices all ok.
reading the installation instructions it says that once installed you should spin the wheel and the speed sensor will flash the green light 5 times to confirm it is working ok.

however, when i took the sensor out my pocket to start to fit it, it was already flashing and stopped shortly after.
now when i spin the wheel nothing flashes, as i assume the sensor thinks it's already set up?

do i need to reset this and make it flash whilst on the wheel?
also, will it auto detect the size of the wheel? as the edge 25 has no settings for wheel size etc.

the cadence sensor was fine, as that didn't start flashing until i installed it on the crank and span it a couple of times.
  • 0 over 7 years ago
    The green light is merely letting you know that it's woken up. It won't wake up again until it's gone to sleep. Pairing only requires that the sensor is awake... I paired mine before fitting it (in case it was dead).

    Wheel size option only appears on every other Garmin device when the sensor is paired and awake.

    There is no intelligence in the sensors, they will broadcast whether there is a head unit present or not. The act of "pairing" is more like tuning in to a radio station - in this case the sensor ID is analogous to the radio station's frequency, and one sensor (radio station) can broadcast to many head units (listeners)
  • 0 over 7 years ago
    yes i paired mine too before fitting.
    interesting though that when i paired them i never saw any light flashing to say they were awake.
    they were sitting on my bed at the time!

    anyway, i'm not sure if the edge 25 has a wheel size setting even when the sensory is paired and awake?
  • 0 over 7 years ago
    hmmm

    I would need to look at an Edge 25, but on other Edge models the wheel size is an attribute of the sensor, so I don't see why it would be different on the Edge 25. The Edge 25 has no option to manual set the wheel size, it is automatically configured to continually monitor and potentially change the wheel size based on the GPS data it is processing. If the GPS is off then the wheel size will not change.


    but then with the speed sensor the device won't be using gps to monitor speed?

    so if the sensor is installed and there is no option to set wheel size, how does the sensor accurately report speed?
    the sensor is attached the wheel hub, but surely it would need to know something about the wheel to be able to calculate the speed?

    even with my old cateye device i had to tell it the size of the wheel to it could calculate speed correctly.
  • 0 over 7 years ago
    It will use the GPS to calculate the wheel size. Then (in theory) it should favour the speed sensor over the GPS for the speed source.