Innacuracies of power and speed with Kickr

(Guillaume Dougados) #1

First ride today was fun but I noticed the power reading was all over the place. While the Wahoo app was reading a very stable power, which I also get from TrainerRoad, Zwift was constantly jumping +/- 25 watts.

Same thing with speed, I noticed up to 8 mph variations. Usually when going uphill Zwift reading was lower and downhill Zwift was higher.

For example uphill Zwift was showing 8mph while I was riding at 16+ mph. Downhill I got a 40mph unlock which I did not deserve as my max speed was 32.66 mph per Wahoo’s app.

Total ride mileage on Zwift shows 12.4 miles while Wahoo says 13.59. Over 3 laps it’s a significant difference.

(anon18154799) #2

Remember, the speed of the Wahoo App doesn’t necessarily correlate with Zwift. Zwift calculates the speed based on power, weight, slop, and aero factors. The Wahoo App has no way of knowing when you are drafting someone on Zwift. The power differences may be the reporting time 1s, 3s, 5s, 10s, etc. Not sure what Zwift does, but it normally is in line with my fluctuations on the road.

If you are using your Kickr with Zwift, you don’t need the Wahoo App open. Just connect your Kickr to Zwift, and it will slave in. Have multiple control connections may have contributed to your issues. Or not. I’m not a tech support guy.

(Guillaume Dougados) #3

I had the Wahoo app open just to compare.
The power should not fluctuate as much as it did. As far as speed, you have a point, not sure but since Zwift is controlling the power I would assume the speed would go along. If I turn the crank at X rpm and power is Y, the speed should be the same on both apps, I think, maybe I’m wrong.

(Ron Sines [odz] B) #4

Speed will be different on Zwift then on the Wahoo app, but the power should be the same, Power is very smooth on my kickr. Is your’ ant+ stick close to your’ kickr? Have you done a spin down test lately?