Calibration, Spin down, KICKR confused...., recommendations

Everything worked fine until yesterday when I did a spin down on my KICKR Snap and what should have been a fairly ‘easy’ workout today turned out to be extremely hard. Not sure why that would screw things up, but that was the only thing that changed. My wife had the same issue with her workout in Zwift.

I’d appreciate some feedback on the recommeded way of doing this as the spin down can be done in both Wahoo or TR (or for my wife Zwift)

How can you tell if a spindown/calibration worked (i.e. you don’t end up with what feels like incorrect power)

Does a calibration in Zwift interfere with a TR calibration?


I’ve had similar issues with my Kickr Core and Zwift (I use an iPhone and/or Apple TV for all my workouts, no PC in my mix). Not sure whats going on but it resolves if I shut down all the apps that could pair with the Kickr, unplug the Kickr for 20 seconds or so than plug it back in. Often, just unplugging the Kickr does the trick so try that first.

It appears to me that the Kickr does not like multiple apps being open especially when Zwift is in the mix.

  • No. Presumably if you use any app that has a proper calibration process, that data will push to any other app. That said, some apps are better than others for repeatable use. The Wahoo app and TR are solid for the Snap. I am not sure I trust Zwift for any calibration process.
  • How often have you been calibrating the trainer before this issue?

    • Wheel-on trainers like the Snap should be calibrated each and every ride, to account for differences in tire pressure and roller pressure. This is important to maintain accuracy and consistency in power data results.
  • What exactly was your process for calibration?

    • Notably, it is recommended that all wheel-on trainers like your Snap get calibrated only after about 10 minutes of use. This is to warm up the tire and trainer components to their operating temperature, to give you the best calibration results.

I rarely do a calibration as the trainer is always in the same position and I check the tyre pressure regularly. As I said before, all this worked pretty well (TR & Zwift) for at least 5 months (which is when I bought the trainer)

As I did a Wahoo firmware upgrade, I thought I might as well do a spin down too. As I had issues (at low watts) before, I now always do a factory spin down which consists of three minute warm up and 2 spin downs.

I didn’t calibrate TR after the factory spin down as I thought that wasn’t need.

Also not sure how it could be so much out of whack that I find it very difficult to complete what should the last (and easier) week of the training plan build phase. For example, I did a workout last week with large section with a target of 97% FTP and my avg HR was 2.3z with the max 3.3.

The (supposedly) HR for the easier workout was avg 3.7 with a max of 4.5

Still somewhat confused

I can’t give you hard reasons behind what exactly might be happening, but your practices don’t align with what I understand are recommended practices from any of the wheel-on trainer makers.

  • The all recommend a regular calibration, every ride after about 10 minutes warmup. It may well be unnecessary in some cases, but without separate confirmation via a power meter, it is guessing.

  • The Factory / Advanced Calibration from Wahoo is not recommended for regular use. It is only meant to be done after major changes like firmware updates, changing the trainer location / environment in big ways, or similar large changes. That is part of the reason it is usually “hidden” and not readily accessible when compared to the normal calibration.

  • Like any piece of tech, it is only as good as we use it, so following manufacturer recommendations is what I suggest as well. Skipping calibration may seem like a non-issue, but it leaves the door open for inaccuracy and potential chances over time.

    • I can’t say for sure that doing Advanced calibrations frequently is “a problem”, but I have seen comments via Wahoo that they are not meant for regular use.
    • It’s entirely possible that drift happened and your recent calibration “reset” the trainer enough to feel like a problem now.
    • It’s also entirely possible that you are experience a legit problem with the trainer that may or may not be related to the calibration in any way. It’s not something we can really diagnose with the info we have.

As to your core issue, I can only suggest doing a regular calibration now and in the future to see what happens. If you have continued issues, you are probably best to contact Wahoo support.

Thanks for your feedback.

Did a TR calibration for myself (and a Zwift for my wife) and everything is back to normal.

Given that the calibration needs the gear to be ‘warmed up’, one could do this after one of the workouts every week.


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