I was exasperated by my Wahoo KICKR performing faultlessly in the evening, but consistently failing during the day.
Every time I would set up for an afternoon ride, with sunshine streaming through the window, the KICKR would always read 0W. There was no Bluetooth connectivity issue, and the fault was constant on both Wahoo Fitness IOS app, and with Zwift on a variety of platforms. I tried them all.
Following advice from Wahoo, it turns out that the optical sensor can be “blinded” by sunlight, and will fail to read the rotor properly.
I made a sunshield for the sensor out of electrical tape, and now everything is working fine.
Get a piece of electrical tape and fold it lengthwise with sticky side in. Then, get a second piece of tape and stick the first piece to it lengthwise along one edge. Then, stick the second piece of tape along the top of the KICKR, with the side with the folded over first piece of tape shielding the gap between the rotor and the base (where the optical sensor is located).
Great little “boot-leg” fix but does anyone know what Wahoo is doing to correct this problem? Just spent north of $1000 (as did most everyone else) for this trainer to stay active while working from home and have more family time in the evenings. Didn’t know I’d have to “duck tape” a brand new (and not cheap) device to make it work properly.
Upon further review… My KICKR is less than 3 feet from one of my home office windows, which is allowing sunlight to shine directly on the sensor. I applied the recommended “sun shield” work around from above and it worked temporarily as the fly wheel blew the sun shield up, exposing the sensor to sunlight again. Long term work around for my situation: I hung a dark window covering (curtain) in the window. Worked like a champ! (of course) Special thanks to this community and especially Phil (see his post above) for pointing out this issue with the sensor. Happy cycling!
I have posted about this before on Zwift and TrainerRoad. For me it was the garage door which caused sunlight problems. I’d be spinning away and someone would open the garage door thereby flooding the kicker with sunlight.- speed and watts would go haywire. What made it worse is that sometimes it didn’t recover immediately once back in shade. This made me wonder about other possible causes (RF, temp) so I’ve been troubleshooting all summer. I even received a new PC board from wahoo after a spin down reported a temp way out of range - but possibly also due to sun?
I tried a cardboard wheel box to shade it but that only worked sometimes- causing more confusion.
But, sun is definitely the culprit. It doesn’t have to be direct sunlight (which is why the box wouldn’t always work). Our eyes have amazing dynamic range but it’s seems the light sensor which the KICKR uses to measure speed does not. It also appears that the sensor calibrates itself when you start spinning to but a sudden change in ambient light messes with it. This would explain why putting it back in shade didn’t immediately remedy the problem, at least not always.
It made me wonder why wahoo used an optical system to measure RPM/speed? It may be because the resistance unit is right there and creates a strong magnetic field so a magnetic cadence sensor would not work.
My solution was to move the KICKR so it never gets direct sunlight. A more sophisticated shroud would be needed as a permanent solution if you want to workout and get a tan at the same time.
