Runn sensor wildly inaccurate

Hi all,

I recently bought a Runn sensor as I wanted an as accurate as possible measurement of my treadmills speed. I suspect my treadmill reads a little bit high, i.e. I am in fact running slower than what it shows.

For this purpose I was hoping that the Runn sensor with factory calibration could guide me to be able to run at more precise intensity zones. However, after setting it up according to the instructions (4 strips, 18" apart, test shows it detects all strips) it is simply very inaccurate. At the lowest speed of my treadmill (2 km/h) the Runn sensors shows 6 km/h. Setting my treadmill to 10 km/h the Runn sensor shows 13 km/h, and going all the way up to 22 km/h the Runn sensor shows speeds in the 30 km/h+ range.

I could of course calibrate the sensor to match my treadmill, but that defeats the prupose of the sensor for me as I find my Garmin Epix (gen2) is able to accurately detect my treadmill speed and send it to Zwift already.

Is my device faulty or has anyone else experienced an inaccuracy this large? Reading most reviews I got the impression that the factory calibration should be fairly accurate.

I have updated the firmware using the ConfigurEZ app, as well as restored factory settings several times to no avail.

If I remember correctly the Runn is factory calibrated at 5mph. How does it compare at that speed?

Also, which treadmill do you have?

It’s counting the time that a strip passes from one side to the other, so calibration at a certain speed shouldn’t really be a thing.

The distance between them also shouldn’t matter. Try removing the strips so you only have 1, and test that. If it’s still far off, it sounds like a warranty issue.

Ran tests at different speeds and it is pretty much constantly at 4 km/h (2.5 mph) over what my treadmill shows at factory calibration.

I did indeed contact support and was immediately promised a replacement unit.