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Watts not accurate after calibrating indoor trainer
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Hi guys,

Yesterday, I calibrated by Wahoo Kickr Snap through Zwift, and my watts went way down. Maybe I'm just in worse shape than I thought, but now it's difficult to hold 50w, and I did an FTP test and my new FTP is 88w. I'm a 17 year old boy and I'm very active, and have been riding a lot recently. I've done multiple 100 mile rides, and I've been biking for awhile. Do you think this power reading is accurate? I tried recalibrating it in the Wahoo app instead of Zwift, but it didn't change anything. The resistance in the trainer is also a lot higher for some reason after calbrating it, and it's hard to ride. I 80w is pretty difficult, and 100w feels basically all out. Is there any way to fix this because it would be pretty depressing if this is accurate.

I've tried unplugging it and restarting it, as well as inflating the tires.
Last edited by: Henry Schultz: Feb 18, 24 10:29
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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Henry Schultz wrote:
Hi guys,

Yesterday, I calibrated by Wahoo Kickr Snap through Zwift, and my watts went way down. Maybe I'm just in worse shape than I thought, but now it's difficult to hold 50w, and I did an FTP test and my new FTP is 88w. I'm a 17 year old boy and I'm very active, and have been riding a lot recently. I've done multiple 100 mile rides, and I've been biking for awhile. Do you think this power reading is accurate? I tried recalibrating it in the Wahoo app instead of Zwift, but it didn't change anything. The resistance in the trainer is also a lot higher for some reason after calbrating it, and it's hard to ride. I 80w is pretty difficult, and 100w feels basically all out. Is there any way to fix this because it would be pretty depressing if this is accurate.

I've tried unplugging it and restarting it, as well as inflating the tires.

DId you try factory spin down?
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Re: Watts not accurate after calibrating indoor trainer [s13tx] [ In reply to ]
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How do you do that?
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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That’s going to be an awfully long ride at Lake Placid.
Last edited by: Lagoon: Feb 18, 24 11:26
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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https://zwiftinsider.com/kickr-factory-spindown/ - believe the procedure is the same for the Snap as well as the direct drive Kickrs.

FWIW - the accuracy on the Snap (from my limited experience) is pretty bad even with checking the tire pressure before each ride and doing a pre-ride spin down. I ended up swapping back to my Kurt Kinetic fluid trainer before eventually getting a direct drive one. If you check tire pressure and do a pre-ride roll down (you shouldn't need the full recalibration each time), you should get more stable numbers, but I wouldn't take any one FTP as golden and would recommend also keeping an eye on heart rate/perceived exertion (RPE) for pacing workouts.
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Re: Watts not accurate after calibrating indoor trainer [Lagoon] [ In reply to ]
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There’s no way my ftp is 88w though right?
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Re: Watts not accurate after calibrating indoor trainer [andrewjshults] [ In reply to ]
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I can barely pedal because it has so much resistance though
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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Henry Schultz wrote:
There’s no way my ftp is 88w though right?

No, something is off.
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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Gonna be tough to break 9:00 in the 3k & dominate Ironman Lake Placid if pushing 100w is hard. We're getting trolled with this nonsense
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Re: Watts not accurate after calibrating indoor trainer [dcpinsonn] [ In reply to ]
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Dude, take it easy, he's just a kid. We were all 17 years old once.

@ OP - this happened with my Kickr Snap and I gave up on it. I highly doubt the numbers are accurate. You can try the factory spindown, but for several months my Snap was largely what I'd call 'consistent' as far as what watts I expected to put out and all of the sudden it was like pedaling through mud and it said I was putting out like 120 watts at 90% effort. All that to say, I don't know how to fix it beyond ensure the tire pressure is right, you've turned the knob the right number of rotations, and you've tried the factory spindown - I eventually moved on to a normal Kickr.
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Re: Watts not accurate after calibrating indoor trainer [dcpinsonn] [ In reply to ]
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dcpinsonn wrote:
Gonna be tough to break 9:00 in the 3k & dominate Ironman Lake Placid if pushing 100w is hard. We're getting trolled with this nonsense

I don't think he is trolling, simply a calibration issue. It is not very hard to push over 250 W FTP for a competitive junior. Even if the leg strength isn't fully developed, ~ 210 bpm max heart rates allows them to spin decent wattages despite the restricted gearing.
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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I've seen a snap do this before as well. It's a terrible trainer IMO. Did you get it recently?
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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Haha no probably not. Pink text means sarcasm around here.
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Re: Watts not accurate after calibrating indoor trainer [imswimmer328] [ In reply to ]
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I got it about 2 weeks ago
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Re: Watts not accurate after calibrating indoor trainer [Labrador1] [ In reply to ]
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Yeah that’s very similar to what’s happening to me.
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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My wife has a Kickr Snap from 2017, and this has happened perhaps 3 times over the years. Never figured out any pattern on why, but for some reason after a spin down it just went into "riding through mud" feeling as you describe. We haven't found a repeatable way to correct it, but after spin downs, unplug/replug, untension/retension, etc a few times it just cleared and went back to normal. Despite this it's been a solid and otherwise reliable unit.
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Re: Watts not accurate after calibrating indoor trainer [Henry Schultz] [ In reply to ]
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Did you buy it new? If so, I'd strongly consider returning it and looking at a direct drive trainer (they tend to be pretty reliable so used is also a reasonable option for cost savings). The amount of time and headache you'll save between a Snap and the Core is measurable (very practically, you'll save from having to do a spin down every time you ride).
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