I should probably mention that location as the driver is easier than doing the radian math for rotation. A trick to get around this is to have the driving bone’s location controlled by another bone’s rotation thru a transform constraint. In other words the driving bone becomes a MCH bone with a transform constraint that points to the control bone and map from it’s rotation(min 0 to Max 359) and map to location (min 0 to Max 1) using local space or it might be pose space. Sorry I don’t remember. Then all you have to do is keyframe the rotation of the bone using vector handles while it’s running and aligned handles when starting up or stopping. Then again if you’re a mathematics person then radium math modulo between 0.0 and 1.0 could be easier.
