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    • After three months of running on Zwift with Runn Treadmill sensor and a handful of hours tinkering with mounting, calibrating, and replacing belt stickers, I finally got it to work as advertised.

      The roller coaster of experience went something like this: when ordering it, I was expecting a 5/5 star product as advertised. But after setting Runn up and facing issues with stickers, mounting, calibration, I would have given it 2/5 stars then and there.

      Finally, after multiple rounds of trial and error, I got it to work correctly and accurately, so now I would give Runn 4/5 stars. I'm taking away one star because of a flimsy mounting bracket and belt stickers that don't stick.

    • Key takeaways:

      1. Set at least 30 mins or more to unbox, mount Runn sensor, and to apply belt stickers. Slowing down and taking time to set up will pay huge dividends in the long run. I had to redo the entire setup multiple times, not recommending it.

      2. Measure the length of the treadmill belt and decide on the number of stickers to use. After a few trials, I found 8 stickers for walking or 4 for running to work best.

      3. Glue the stickers directly onto the belt. Else stickers will fly off the treadmill belt and need to be reapplied. Whiteout markings don't work.

      4. Calibrate the hell out of Runn sensor. After multiple rounds of sticker applications, I measured precisely the entire belt and positioned 4 stickers down to a millimeter apart. Since then, the pace is precise and more accurate than the treadmill reports due to belt slippage.

      5. Pairing with Zwift is easy and straightforward. No issues at all other than incorrect elevation reading, which I think, is the issue with Zwift.

      Now that Runn is set up and working as advertised, I love the fact that it is permanently attached and charging on my treadmill. The convenience of having it on and ready anytime is a huge deal for me. I share the treadmill with my girlfriend and dad, so they too get to walk and run on Zwift.

    • Runn, Stryd, and Garmin Footpods

      When I first ordered Runn for $99 (now on sale for $79), I expected it to make my $219 Stryd running power meter pod collect dust on a charging station. Stryd has been my gold standard in terms of accuracy until Runn. I only use Stryd on a treadmill, even though I can run with it outdoors.

      Garmin foot pods don't have a good track record in my experience running on Zwift. I had to use two Garmin foot pods calibrated for different running speeds and had to decide in advance which one to use. Couldn't do intervals or mixed pace runs with the correct speed and distance reading. What a pain it was!

    • Unboxing

      Runn sensor and mounting bracket (cradle) is the first thing you'll see when opening the box.

    • Under the sensor, you'll find a manual, micro-USB cord, belt stickers, and double-sided adhesive strips.

    • Setting up Runn on a treadmill

      I set up my Runn sensor in front of the treadmill. It is closer to the outlet and permanently plugged in with the included micro-USB cable and a 5V USB charger (not included). I'm using a spare Kindle charger, but most iPhone or Android phone slow USB chargers should work.

    • When setting up the Runn sensor, the recommended distance between it and the treadmill belt is 0.25 - 0.5 inch (0.6 cm - 1.2 cm). The manual suggests using a pen or pencil as a guide.

    • Unfortunately, my Boston Marathon 4.0 treadmill design has sloping sides, so mounting Runn sensor leveled was a big problem. I had to use multiple strips double-sided mounting tape to get it leveled. Didn't get it right from the first try and had to remount it again after a couple of weeks.

    • The mounting bracket has to align with the treadmill belt perfectly. The bracket itself is very flimsy, and I hope NPE will take consider that feedback and make it sturdier. When running hard, the sensor can and does fall between the grooves and slides back and forth. Maybe it is a "user-error" aka me accidentally tapping it with a foot while running, but that should be a design consideration.

    • I had to stop the treadmill a few times to reposition the sensor inside the bracket. Finally, I decided to create a custom bumper and permanently mount it inside the bracket. This way, the Runn sensor sits on top of the bumper and can't fall any lower.

    • Here is how the bumper fills up the space between the sensor and the base of the mounting bracket:

    • How many Belt Stickers to use

      Belt sensor stickers are the most annoying part of setting up the Runn sensor. Figuring out the right amount of stickers for my running pace, positioning them properly, and hoping they won't fall off, is an art form.

    • First, you'll need to figure out how many stickers you need based on your running pace. I started too generous, placing stickers every 12 in (30 cm) apart on the belt. The thinking that more stickers would give more accurate sensor reading. Right?. Wrong!

    • The Runn sensor gets overwhelmed with reading too many stickers while running. On Zwift, you'll see an avatar speed up for a second then completely stop on and on. After painfully realizing that I had to take out the measuring tape for the nth time.

      The solution was to place only four stickers positioned precisely 33 in (83.8 cm) apart. That works for my treadmill's belt length and my preferred running pace of 7:30 min/mile with 6:00-6:20 min/mile intervals thrown in once in a while.

    • How to keep Belt Stickers in place. Whiteout?

      Keeping stickers from flying off the treadmill is a big issue. Treadmill belts have a bumpy surface for traction, which is the opposite of a perfectly smooth surface that helps stickers stay in place.

    • I tried cleaning the belt with rubbing alcohol and pressing stickers as hard as I could and hold for a solid bond. But inevitably, after a few runs, they would fall off, and I would have to take out the measuring tape and reapply a fresh sticker. Very frustrating.

    • I decided to try a whiteout correction tape. It seemed like a good idea until I tried to mark the treadmill belt. It turns out the same bumpy surface prevents making a clean mark. That was a major fail, and I had to put more fresh stickers back on the belt.

    • After a few weeks of running, the stickers kept falling off. So, I decided to order an actual whiteout liquid to try. The liquid solution was much better, and I got solid markings on the running belt. But it didn't work as expected. Why? Because the Runn sensor didn't recognize them at all.

    • After scratching my head, I realized that I never thoroughly tested the theory of using whiteout only markings without any stickers before! In all my runs, I had a mix of both stickers and whiteout markings. So I assume they worked.

    • The final solution was a combination of stickers glued on top of whiteout markings spaced out at 33 in (83.8cm) apart. It worked!

    • Runn Accuracy: Pace, Distance, Cadence, and Incline

      In total, I've done at least 10x5km, 4x10km, 2x21km (13.1 miles), and 10+ runs between 4-10 miles (6.5km - 16km) on Zwift with the Runn sensor.

      When properly calibrated and mounted, it provided very accurate readings for pace and distance. The cadence drops here and there during the run, and is accurate, but not reliable. The incline is useless for Zwift, so I don't know if it even works.

      Here is an example of a steady pace half-marathon run on Zwift with a few bathroom breaks. This is probably the longest I would ever want to run on a treadmill.

    • Same half-marathon run on a treadmill 13.4 miles instead of 13.1 miles reported by Runn. I'll take it!

    • Here is a 10km (6.2 miles) interval runs at 7:30 min/mile pace with 6:20 min/mile intervals.