So I want to achieve a car rolling on one wheel, and lacking all parts but a seat and the wheel. Though, I have tried a lot of stuff to prevent seat from rolling with the wheel. Here’s a basic drawing of what I want to achieve. I’m sorry if you couldn’t understand me, my English is kind of terrible, not my first language.
Not sure if this’ll work, but you can give it a try
Place a 1x1x1 studs part and move it inside the ball, then use socket or hinge constraint to attach it to the part, then weld the seat to that part, and you can add a bodygyro inside that part to stabilize the seat