What is the device behind the saddle on all the riders' bikes in the 2015 tour? I'm seeing it on almost every bike. It looks standardized and electronic.

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2 Answers 2


This is a special device that gathers the following data, according to this article:

  • the stage winner’s top speed, average speed and time per kilometer

  • the fastest riders up key climbs

  • the speed of the winner at the finish line

  • the top speed achieved by a rider on the day

  • average speed across all riders

  • Why isn't one of the big guys like Garmin already doing this, or rather, why didn't they beat Dimension Data to the punch?
    – ebrohman
    Jul 7, 2015 at 17:04
  • Most likely because they are already sponsoring a team and there's only so much money in the marketing budget. Plus having title sponsorship of a team will deliver far more impressions than an unbranded foxtail device bolted to the back of a saddle.
    – ChrisL
    Jul 7, 2015 at 18:35
  • 2
    Basically a GPS tracker.
    – super
    Jul 8, 2015 at 7:01
  • 1
    doubles as a miniature mud guard
    – John
    Jul 15, 2015 at 22:15

They are GPS trackers with a wireless data connection, GSM or EDGE would be enough for the data rate, but it might be something faster. The company supplying them is Dimension Data you can sign up for a free data report at the end of each stage here.

  • GSM (i.e. 2G, 64 channels per antenna) is no longer supported in some advanced parts of the world (Germany IIRC), the frequencies are reused for faster mobile communication technologies. Apr 9, 2019 at 8:40

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