“Trainer Difficulty” was a poorly chosen name which confuses many new users. There are good explanations what this slider does on Youtube and on Zwift Insider. In a nutshell, it is not trainer difficulty but trainer realism. When you move it to the left, you do not feel the terrain - you do not feel the impact of uphill and downhill on resistance, and your bike barely tilts. When you move it to 100%, it is full realism, your bike tilts all the way and you need to switch gears like in real life. And of course one should not forget to press the “unlock” button on KICKR BIKE console before the ride, to allow it to tilt.