This week, I migrated from a Kickr Snap to a Kickr Core 2 with Zwift Cog and Click. Since then, my average power output has been cut in half, from an average of 250 watts or more to 125 watts at the same cadence. I updated the firmware as directed, but it made no difference. Has anyone else experienced this?
wheel on trainers are notorious for over estimating power
There’s also the issue of going from physical gear changes to virtual when you switch from the Snap to the Core. While there should be some general change in your power, a 50% drop is a bit much. Zwift tends to default to a pretty low gear when starting up a ride (for obvious reasons), so double check that you aren’t in a granny gear and then see what power you get for a known cadence.
It’s possible, but Wahoo’s documentation claims accuracy of +/- 2% for Core and +/- 3% for Snap. That’s seems negligible.
I’ll do a test and record the results with different gears and a constant cadence.
Those tolerances are under ideal, steady state conditions. IE, if you input a steady 200W’s to the Core trainer, it will report between 196 - 204W’s to Zwift. But, there are a number of different ways that a wheel on trainer like the Snap can get mis-calibrated and develop an offset. IE, you’re putting in 200W’s, but the calibration is messed up and has a +50W offset, so the tolerance would be around the inaccurate 250W’s the Snap thinks its getting, not the 200W’s you’re putting in.
I connected to the Wahoo app and my power data was nearly spot on with what I was getting with Zwift before the upgrade. I could comfortably achieve and maintain 20 or mph with 70 to 80 RPMs and about 250W. I’ve gone through all the settings for Zwift and can’t see anything that has changed.
Someone else mentioned the new core 2 taking a while to autocalibrate and it took a few rides before it was dialed in, maybe the same issue here?
The accuracy of the Snap depends on proper setup and frequent calibration, so all bets are off if there are any mistakes or inconsistencies with it. I can’t say if that affected you or not. You would need to dual record with a power meter on the bike to know which one is more correct.
To clarify.. If you connect the Core to both Zwift and the Wahoo app, in Zwift you’re getting in-game wattage that’s about 1/2 of that showing in the Wahoo app?
That is correct. About 50%.