u/bergen7563

Hello everyone,

i have a Pacer Pro with the old Bluetooth strode sensor. today I went for a run to check the course of my next half marathon. the watch reported a distance of only 18km!

i have accurate gps measurements every 1s and I waited for a full gps look down before the start. i even had to calibrate the watch because I followed a GPS course.

i am very confident I actually run 21km and not only 18. what could have been??

how can I be sure this does not happen on race day?