Kickr Snap suddenly drastically different in power after calibration?

hi all, i just had the same issue as above. i used Zwift to recalibrate (i’ve go a Kickr Snap) and following that, the displayed power dropped significantly (felt like i was riding ~300W and it was displaying as low 200’s.) i tried a few different options, in the end i unplugged the Kickr for few mins, then plugged back in and tried the wahoo advanced spin down (basic spin down wasn’t fixing problem even after tightening and getting spindown time down to about 18s). i kept tightening until it got to ~16seconds and now the power is showing OK on Zwift.

Thank you Timothy for starting this conversation. I also just cleaned my bike and replaced back tire a week ago and have been fighting to get through my workouts ever since. It wasnt they were easy but like the comments have replied… a little like MUD!
It’s hard to put your finger on. I have re calibrated with Zwift and Wahoo and it has not adjusted the problem.It’s very frustrating. I have spent so much time getting it just right and have enjoyed Swift with friends. But now I can’t even stay close to them on a ride.
It has been very discouraging to have dropped so much in my ability to attain the same level of power as I did prior to the tire changing ect.
I am going to try the advanced spin down. I have a Kickr Snap.
I am hoping it helps. The support from Wahoo is not really there at the moment.
At least I know I am not alone!!

Seems like everyone who has this problem has a Kickr Snap. I went for nearly a year, working several times a week, to build my FTP to what I thought was almost 350w. It took a lot of work. I rode on Zwift and did hard workouts at least 3 times per week. I completed the whole Zwift Academy, and did the little races and stuff. When my trainer recalibrated it called into question all of that work, and made me question the accuracy of anything that happens on Zwift.

Having the exact same issue now. Power is 20-25% off relative to what I’m producing on board my wife’s Hammer and what it was just a week ago before I attempted to re-calibrate in game. It’s now super unstable after sprints and seeing power decreases when out of the saddle.

Beyond frustrated.

I might try to return mine for a wheel off trainer. I bought my Snap just under a year ago at REI.

FWIW - I have never used a real power meter. According to the new training program I’m using, my current FTP is 268. I wondered how accurate that might be so I looked back at my Strava for a segment that I did at pretty close to full gas for around 20 mins. Something that represents the closest thing I’ve ever done to an outdoor FTP test. It’s a flat 7 miles on our bike path that involves some little twists and turns. I did 24.2 mph average. The segment took 17:27. That’s my PR. Strava estimated 240 watts. So, if you figure coasting around the turns and up and down bridges, I would say 260-270 FTP sounds about right.

What I guess I’m saying is that I was probably nowhere near the 350 FTP I thought I had.

I have found the same issues with keeping up competitively on Zwift as my power records at a lower level than it should. It doesn’t affect the quality of my workouts as much as it does the overall joy I might be able get out of Zwift. Comparing to peers on Strava my avg watts for a ride I will be at 185 whereas those I ride with outdoors are at 270. I understand that they could be going faster than me but that differential is not realistic.

tldnr: kickr snap power is rubbish, the spindown is a joke. You can ride with to low power numbers with the spindown, or too high without.

Long version:
Hey. This is a while ago, but I comment anyway. I ride with an extra training wheel as well. always calibrated my kickr snap every single time as said in the manual (and which is super annoying). With 10 m warmup and making sure spindown time is between 10 and 15 seconds. and had over time risen my ftp from about 180 to 220. I just thought I maybe don’t have the genes for cycling, running being my first sport anyway.

A few weeks ago I invested in a new bike with a powermeter and it turns out, I can do a 15 mins climb averaging 300 watts, and more than one per ride. (Which matches roughly with calculated power on strava, but I thought strava just wants to stroke my ego so I buy premium). While 270 watts is my max 5 min effort on the snap and then I’m done.

New bike has thru axle, and I won’t buy the upgrade kit from wahoo. So I can’t directly compare the power meter with the kickr snap.
They don’t see money from me again, next trainer is a tacx :man_shrugging:

Any chance you tried putting the old tire back on? I’ve also just changed my tire and I’m having a horrible experience with the new one. Can barely pedal. I’ve tried recalibrating etc, and I think the only thing left to do is put the old tire back on and see if it goes back to normal.

My Snap read low power for almost 2 years, I’m not a high power rider in the first place. I think it is essential to do an advanced Spindown when you take delivery as you don’t know what has happened between manufacture and delivery. Then you need to do one every few months as it gradually changes over time - so why the heck is it hidden!!!
Once I started pumping the tyre harder (over 100psi) and being sure my spindown was under 15 seconds and doing a proper warmup before the spindowns it came right. It’s like the trainer calibration moves over time and the only thing which can fix it is the advances Spindown which adjusts the braking factor. Finally it felt spot on, but I only knew it was working right when I compared my effort and power to a Kickr Core (I guess they could both be out but I don’t think so),
I wish I had an independent power meter to compare the Snap to but I didn’t, I thought I was just useless!
One way I found that gave me a clue something wasn’t right was to pedal at low power. If I was still putting in an OK but low effort and I stopped in Zwift then something had to be out. Only the advanced spindown appears to fix that. I found the standard spindown only adjusted the bias of how easy/hard it was to go uphill or downhill, ie easy up and hard to go down or in my case almost impossible to generate power going up but I could generate twice as much with no effort going down.

Not sure if that helps, but that’s my experience.

When I bought the Snap I felt the power was too high. Prior to lockdown I was using the Wattbikes at the gym. Since the firmware update I feel the Snap is more realistic and in line with my Wattbike power. I feel satisfied now more then ever with the Snap.

The issue is the consistency. I guess I wouldn’t really care if the Snap was inaccurate (low or high), if the power was consistent so I could actually train to consistent numbers. Instead, the power is all over the place. Erg mode is unusable as the tension ramps up so high I can barely move. I climb steep climb hills here locally, and tension in erg is worse than anything gravity has to throw at me.

Anyway, FWIW I’m still using the Snap, just with TR and not Zwift anymore. I used it for an hour this morning actually, but, in the first 5 mins I noticed that 300w felt waaay too easy. I did a spin down in TR. Suddenly 250 felt like 350 did previously. It’s frustrating but I try not to think about it too much. One of these days I’ll spring for a wheel off trainer that I imagine has none of these issues.