As I run the same route through the winter (three or four days a week anyway). I will try the calibrate button after my next run and make the thing believe it has run 4.47 miles to see if that improves the readings.
I am using my Nike + sensor in a pair of Nike Pegasus+ trainers that I have just bought with a nano 7th Gen.
I tried to calculate the distance of my daily run using a few map sites and they all say 4.41 to 4.47 miles. The first run with nike plus said 3.84 the second said 4.04 (I had not calibrated it).
Anyway, I looked at a 1/2 mile route using map my run and then tried to calibrate the sensor. I ran the route until the voiceover told me that calibration was complete and it appeared as if I had run over 50 yards more than suggested by the end point on the map. On a plus, the trainers are very comfy.....
Does anyone have any ideas? What do I believe, the map or the nike+???