Hello! Been biking on Zwift since Jan 2024. I use a KickrSnap trainer connected to Zwift on my iPad. I connect the trainer to measure power (I don’t use resistance) and have a cadence sensor. I was able build my FTP up to ~160.
I’ve had no issues with Zwift so far until the latest update. Now my power numbers are way low where a 140-watt effort is measured to be at 80 watts or less. I even went all out with the gearing maxed out which would get me up to (pre-update) 400-450 watts for a quick second or two, but since the update that same effort barely hits 200 watts.
I’ve tried a spindown both on Zwift and Wahoo and I didn’t get any error messages. I’ve tried “resetting” the trainer, deleting and reinstalling the Zwift app (and the Wahoo app for spindowns). I do notice when I open the Zwift app, it immediately causes the trainer to increase resistance before I even log in which did not happen before.
I am not sure if Zwift support/tech team can see my data prior to the update and after the update if there are any changes in the data feed. I feel like something is corrupting the data from my trainer and I cannot for the life of me figure it out.
I am hoping to get some help/advice on additional ways to resolve this, or if there’s anything I overlooked??
Have you checked your tyre pressure and roller tension? Wheel-on trainers are very sensitive to their setup in this way
Zwift just takes the power that your trainer reports, so if Zwift is reporting much lower power, it’s because your trainer is reporting lower power, hence just a coincidence with the timing of the update.
I would check the trainer/wheel setup in the first instance, which you haven’t mentioned here.
I will double check the trainer/wheel set up. I haven’t mentioned it because I felt it was not a variable because I did not adjust the trainer or remove the bike before/after the update.
Hey there @Milo_Leon Welcome to the Forums! I’m Norman from Zwift. It’s true that Zwift only reads the power your trainer generates, so this issue coming up just after the update is likely just bad luck.
I’ll recommend doing the spindown calibration in the Wahoo Fitness App only, the calibration is stored in your trainer, for third-party trainers, it’s always better to have it calibrated in the manufacturer’s app.
Also, while you’re in the Wahoo Fitness App, I’d recommend doing some testing, if the power output is also low over there it’d be a good idea to contact Wahoo Support.
Update- tire pressure set100 psi and I adjusted the tension on the trainer/wheel. Spindown on wahoo was ~19 seconds. I still have oddly low power numbers
Good news with this update! The issue has been resolved - still not sure how/why it occured in the first place.
I did what Norman recommended and went into the Wahoo app again. I did a test run and immediately power numbers were back to what I expected with my given efforts. I rode for about 15 minutes and everything looked great and did another spindown (~15 seconds) to re-calibrate.
I also went into settings and turned off ERG Smoothing mode- it was the only thing enabled and it has always been on. Never had a problem but figured lets try turning it off.
Force-quit the app and opened Zwift for another ride and everything was going smoothly and power numbers seems accurate now
If the Zwift Hub has auto-calibration and you should use the manufacturers app for others, why is there still the option in Zwift to calibrate trainers? Seems like it may cause more issues than it helps.
