I recently purchased a Stryd to use with my 235, mostly to get an accurate pace/distance measurement on the treadmill, which I use quite a bit. After several session on the treadmill, outside with GPS turned off, and outside with GPS turned on, I have come to these conclusions:
1) Stryd is scarily accurate. On the outside runs with no GPS, Stryd was no more than .02 miles off.
2) Stryd seemed very inaccurate on the treadmill. My pace was anywhere from 1:00 to 1:20 slower than my average training pace on a typical outdoor training run.
3) Upon looking at all the data, I found that my average stride length was anywhere from 7 to 8.5 inches shorter on the treadmill. While I have heard that this is not uncommon, I am wondering if it is unusual to this degree.
My conclusion is that Stryd is getting my pace and distance measurements on the treadmill correct because of both the accuracy of the outdoor runs and the accuracy of other metrics (such as cadence). I am wondering if there is a way to adjust either my 235 or Stryd to compensate for my short stride? In other words, could the treadmill run be somehow changed to take the recorded metrics and calculate the distance using my average outdoor stride length? I am pretty sure that more goes into a treadmill run other than stride length, but I would like to somehow "match it up" to more closely mimic an outdoor run. Calibration doesn't seem to be an option since it has been very accurate on indoor runs outdoors.