Wahoo v Zwift Spin down?

Hi guys,

Which spindown is considered more accurate when using a bike on a wahoo kickr core?

When I first started riding my average watt output for 20 mins on relatively flat routes was 230w. However, when I performed a spin down using Zwift my speed and distance performance dropped significantly. I struggle to almost get about 130w on a 20 minute relatively flat ride with a few hills. I am 25, 70kg and relatively fit.

Just wondering if my speed and power is an illusion and there is something I am missing on the setup?

I have added three photos covering different measurements I have done.

Photo 1 - Yorkshire is my performance after the Zwift spin down.

Photo 2 - A race I did after a wahoo spin down.

Photo 3 - Cycle I did in London on a Brompton with loads of traffic lights.

Any help would be greatly appreciated.

Based on your speeds I don’t see an issue with the power output but personally I would recommend doing trainer calibration using the Wahoo app. Make sure you’ve warned it up, make sure your trainer software is up to date and then do a calibration.
After you’re done make sure you completely close the Wahoo app else Zwift may not connect. It’s a Bluetooth thing.

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Well, I certainly see the difference of the 2 calibration techniques: 243 watts vs 95 watts.

I think you mislabeled photos 1&2. (photo 1 is Crit City and photo 2 is Yorkshire).
You don’t have a power reading for outside so we have to look at courses and speed.

Your IRL ride has you at 4.8 miles over 21 min with 82 feet elevation and 13.5 mph.

Wahoo ?? crit city race (243 watts) 7.5 mi, 17 min, 328 feet and 25 mph.

Zwift Yorkshire (95 watts), 4.8 miles 22 min 413 feet 12 mph

I would say of the two, the Yorkshire ride most closely resembles your IRL performance.
This conflicts with the usual adice that it is best to use the calibration app for your specific device and not use the Zwift calibration.