Resistance not matching course

IPad / wahoo Kickr Snap… tonight I was on what I thought would be a gentle ride in Watopia. Things got a bit odd. When apparently travelling downhill resistance increased, at times markedly, while I was flying uphill. Except Zwift had me travelling really slowly uphill. At one point, in the Flats, Zwift had me up around 40km/h but I was in a really low gear struggling to exceed 12km/h (Garmin Edge 820/speed sensor). What’s going on? Is it me?

What is your ping time to central California? Check here:

High ping times can cause issues.

180ms or so. It worked fine until yesterday. Thanks for your suggestion

Anything over 50 and you will see issues like this.

Using netAnalyzer to ping I consistently get under 50ms

Are you using ANT+ with a USB extension?

Zwift and your speed sensor will not show the same speed. Zwift take the terrain and weight into account, garmin ony wheel speed, the garmin does not know how hard you are pedaling.

You need to make sure the trainer is clamped tight against the wheel and you need to do a spindown calibration when the trainer and wheel are warm.

also check that your Zwift software are up to date.

Hi Gerrie, those are just examples. I would expect Zwift to show a much lower speed if I am barely turning the wheel. At the other extreme, Zwift gave really bad figures when my Garmin was flying.

IPad linked with Bluetooth. I use ant+ to connect speed sensor and hr strap to Garmin Edge to give a separate record of energy expended.