Wahoo KICKR Snap Accuracy or is it actually the TrainerRoad app?

A while back I posted a thread complaining about how I suspected my Wahoo KICKR Snap wasn’t accurate. I resided to the fact that it was likely my legs to blame for a lower-than-expected FTP.

I don’t have a power-meter to test it against, but after 5 weeks of training, yesterday I decided another Ramp Test was in order. I had previously attempted two of them (discarded one).

The story goes like this. Start Ramp Test, experience very elevated heart rate levels at wattages that are a full zone lower than what I would expect those values to be at, (I.e. Z3 heart rate at Z2 watts.), attempt to persist, and finally blow up before even reaching my target wattage that would give me my current FTP (260w). We know that the Ramp Test takes 75% of your highest 1-minute power, so for example, that would be: 347w for a person with an FTP of 260. On 3 attempted Ramp Tests I couldn’t even hit that number.

The solve?

I decided to do an advanced or Factory Spindown on the Wahoo app, thinking that there HAS to be an issue with accuracy. After doing this, in a moment of frustration, I decided I’d do a power test with the Wahoo app and see what I could do. This turned into a 2x8-min FTP test in which this happened. 334w and 337w NP for 8-min in a garage with 80º F ambient air temp on top of a fail Ramp Test that was attempted 10 min prior. So, less than ideal testing conditions. Totally baffling. How could this be? I just bailed on a Ramp Test 10 minutes earlier in which I could even hit the same power numbers?

This leads to two conclusions. My FTP is actually 300w and the Wahoo app is displaying accurate power. TrainerRoad app is broken and is displaying inaccurate numbers. My trainer needed a factory spindown all along. Or I massively overachieved on the 8-minute test.

I wish I could be more scientific with this, but regardless. Something is/was off and I’m hopeful that it’s now fixed.

Anyone else have similiar experiences?

May not make much difference if you were smooth, but you should be using Average Power, not Normalized Power to grab for calculations of FTP in the 2x8 or 1x20 tests.

If I follow the order right, you haven’t retried the Ramp test since you completed the advanced spindown?

Seems like that is worthwhile for another data point as a possible comparison to your 2x8, with the same trainer variables in place.


I stand corrected, the average power for interval 1 was 335w and 338w for interval 2.

I will be resuming training via the TR app after having done the factory spindown. My hope is that the spindown removed any sort of inaccuracies the trainer could have had and that I can resume training and complete the upcoming workouts at an FTP of 300w.

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That works. See how the workouts feel vs what they should be and you can fine tune from there.

Did you take the bike off and on the trainer in between the trainerroad test and going on the wahoo app? I find my kickr snap is very sensitive to how tightly you apply the roller to the wheel and you may have inadvertently tightened it less when using wahoo as opposed to TR??

I left the bike on between tests. Prior to the TR Ramp Test I actually had to add resistance to the wheel/tire. I gave the knob an extra 1/4 turn before trying the TR Ramp Test. It’s been very warm, and I was getting a spindown number in the 17s range and know that Wahoo advises it to be between 9-16s.

Maybe you can’t answer this, but I would think that now having done a factory spindown, the trainer is in a “more accurate” or “truly accurate” state and that I can expect consistency, even between multiple apps (Zwift, TR, Wahoo, FulGaz, etc)

Fingers crossed.

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That is the hope. I’ve heard of good improvement from most people who’ve performed the advanced spindown. It’s still a good idea to keep your tire and roller pressure consistent, and do a regular spindown each workout after a 5-10 minute warmup. Then you should be getting reliable data and performance.

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I personally had awful repeatability issues with 2 Kickr Snaps. I could compare them to a power tap wheel and anytime (which was often) I found the devices now matching well I would fumble down a hole of normal calibration and the factory one. Getting them to match within 5% seemed more like blind luck than anything scientific in my situations.

I can’t tell, but it sounds like you did a TR test, then calibrated, then used the wahoo app. One would hope the factory calibration is only for the positive (when it comes to accuracy) but I’m not sure that’s a certainty.

I’d assume after your factory cal, going back to TR would yield at least similar measurements, so the answer to the question “is it actually the TrainerRoad app” is probably no.

I think many have SNAPs and like them but in my case I couldn’t bear the constant mental toll of needing to get it calibrated and accurate (at the time I didn’t have a power tap to use with every ride). I ended up getting rid of one in favor of a 2nd gen kickr, and my wife uses the other with the built in ANT power meter connection (via wahoo app settings in the trainer) in which case it seems to perform fine.


You’re correct. For the ramp test I went through my normal protocol of performing a spindown through the TR iOS app and then did the ramp test. It felt exceptionally difficult and my HR wasn’t correlating with the on-screen power numbers. I know there are many factors that can contribute to elevated HR, but 95% of the time I ride it’s within expected values at a given power zone.

Within 5 minutes of ending the ramp test, I fired up the Wahoo app and did a factory spindown and then promptly did a manual workout with the Wahoo app and power numbers were some 40w higher than what I’d typically see through the TR app. I knew at that point something HAD to be off with the trainer prior to doing the factory spindown.

For context, prior to the factory spindown I was using an FTP of 260w for all of my TR workouts, and it felt like the right number, however, I had a hunch that 260w was ~30w lower than my true FTP. After the factory spindown my FTP (estimated from 2 8-min all out efforts, 332 and 339w) my FTP is now set at 300w (3.67w/kg). I think this is a conservative figure.

My hope is that the factory spindown eliminated whatever accuracy issue was happening and that I’ll be able to use the TR app @ an FTP of 300w for all future work and successfully complete workouts at that wattage. I’ll be doing a test workout tomorrow to see how it goes.

Exact same issue with me. I was continuing to fail at a ridiculous low number on the Ramp Test. I did a Factory Spindown, did a 2x8 FTP and tested 50 watts higher. Mine was through TR, so in my opinion, it’s not a TR app vs. Wahoo app issue. I think the Snap just needed a full recalibration, and it made all the difference.