Wow, opposite here. Something like 14mph in little chainring for the first 35 minutes of this TR workout, and 21mph when in big chainring for the 2nd half of the workout:
and here it is on TR:
My color commentary about the test using Colosseum workout here: Big vs Small Chainring - Same Power (ERG Mode Gearing) - #18 by bbarrera
Setup:
- Kickr 2017 direct drive (wheel off) in Erg mode
- Stages power meter
- something like 50x17 in big ring, and 34x17 in small ring
From talking with Wahoo support (and support article), the Kickr 2017 direct drive will report speed based in flywheel. So bigger gear or higher cadence = faster spinning flywheel = higher speed reported.
There is a Kickr setting called “Erg Mode Speed Simulation” that will have Kickr report power based speed, but it has been tricky to get it working reliably (Wahoo doesn’t officially support it with 3rd parties).