Garmin and Zwift not accurate

General Discussion
1

Or maybe perhaps they are not the same. I just started using Zwift on a Wahoo Kickr and also have a Garmin 520 plus connected.

Mileage on the two is very different.

Additional question which might directly relate to the situation. My tire size is 29x2.25 but I don’t see a setting even close to that. Can I customize one?

2

Your Garmin 520 does not know about the virtual elevation changes with in Zwift, so Zwift and the Garmin will hardly ever match.

You can use this link for choosing a tire size: https://support.zwift.com/de/tire-size-comparison-chart-r1R1R1Bm