Help me out...
I have never been on a treadmill that is accurate. Most are not calibrated correctly and even those that are do not seem to be accurate. By that I mean that my various paces are always too slow. I can run on the street and gauge my pace without a watch within 5-10 seconds accuracy. My paces on a treadmill are always way, way too slow.
So, the treadmill, if calibrated correctly, determines your pace by the length of the belt and the time it takes the belt to make revolutions. This does not take into account stride length, which I think is why they are never accurate for me, and rarely for anyone else either. My stride length is longer than the belt, especially at faster speeds. If my stride length was shorter than the belt length my paces on the treadmill would be faster than on the roads.
Am I looking at this correctly????