On Wednesday, January 29, 2020 at 7:34:11 PM UTC-8, Garrett McEwen wrote:
That mechanism showed up for the Twin III, and is for the nosewheel steering. The OP is asking about that thing in the Twin Astir that makes the instructor's hips sore.

Grob devised a novel retraction system for the Twin Astir. The single wheel was designed to rotate 90° sideways before retracting "flat" under the rear seat, resulting in a rather unusual seating position. This was only incorporated in early examples, later on, the wheel was fixed.