My older One-Wheel Stroller Kit keeps pulling off to one side when I use it in Stroller Mode.

For best results when adjusting the trailer tracking, make adjustments while trailer is loaded. With the stroller kit in the “stroll” position, loosen the bolt using a 5mm hex wrench. Using a 25mm wrench, turn the bushing so that the stroller wheel is vertical when viewed from the front. Tighten back up the bolt. You can fine tune as necessary so that the trailer rolls straight.