Always 1w lower than needed on kickr snap


Often times, when I’m supposed to ride at a certain wattage, Xert Shows me that I am one want to low. At 200 wants, Xert shows me that I am riding at 199, add 120, it shows me that I’m doing 119. When I then speed up, advise us a couple of words above the supposed value but even if I pedal at one 120 RPM which is way too high, it then drops again. Basically, I can never hold the exact number, no matter what I am doing. I have done the standard and extended calibration on the wahoo.

Can anyone help with this?

I have been using Xert with a kickr snap, current model for a couple of months now. I arrived about nine hours per week on average. My Fitness is constantly declining no matter what I do. Started slow, had longer rest periods in between, followed the advice on Xert, followed the advice in Polar Flow as well, which was very similar most of the time (regarding my fatigue and training status).


I wouldn’t worry about 1w - it’s less than error range for the typical powermeter.

Re losing fitness, do you say that because your signature is declining (likely due to signature decay if you’ve not had proper breakthroughs) or because you’ve done recent breakthrough efforts, and are getting lower results than you did in the past? If the former, you should do a proper breakthrough effort…

Thanks so much, @wescaine

Re losing fitness, I am saying that because my signature is declining due to signature decay. I had a proper breakthrough last week, when I did a 13 min workout (which I chose on purpose because I wanted to achieve a breakthrough) and just pushed harder than requested. But in the three months before, my signature was constantly decaying without ever having a breakthrough. Seems like, if I just the recommended workouts as requested (ie. not “overreaching” on the required wattages) my watt numbers are constantly declining, and the training volume is increasing.

The decay is a feature of Xert to make it easier to get a BT and keep signature up to date. It’s not representing your actual signature between breakthroughs, which is why they recommend doing a BT regularly (and make sure it’s properly all out / to failure in case it wasn’t)

You can turn off that decay (or slow it down) if you know you won’t go for a BT for a while… eg during base training… it’s in your profile / account settings. In that case your signature increase (and decreases) with changes in training load, which I guess is what you’re expecting to see. I usually leave it on no decay for winter, then slow decay (rather than optimal) if riding more aggressively


Awesome! I knew that I can change the decay but was unaware that if turned off, the fitness signature change with training volume. Thanks for patiently filling me in on this correlation even though I am sure this has been explained many times throughout the forum.

No problem
Still worth doing a good breakthrough from time to time, to check that the predictions are reasonable

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Your last BT activity is shown below your name at top of XO along with a warning triangle (!) if no BTs detected in over 3 weeks. You can manually select a BT workout when you see that warning. One won’t show up on the recommended list automatically.
Search the workout library for “breakthrough” and pick one you’d like to try when form is fresh. Ride it in slope mode, exceeding target watts when practical (without blowing up), plus spin-up and sprint for at least 5-7 seconds on the longest interval right before you collapse.

As @wescaine recommends, change to No Decay if your signature looks good (from last BT) but you don’t want to “test it” with any maximal efforts for a while (ex, base training). Any rise/fall will be TL based.

Over time you will discover there are different ways to achieve BTs indoors and outdoors. Those differences affect which signature values are likely to change the most.

Reference –
Breaking Through the Xert Way! – Xert (

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Thank you, @ridgerider2

for the details. Now I know that BT workouts won‘t show up on the recommended list automatically, I understand that it was good intuition to just choose the 13 min workout. But also, I had not changed from „auto“ to „slope“ mode, so next time, I‘ll do that as well.

Glad to be getting such wonderful support support here!