[KenWittlief]

yes it has to adapt for a range of riders, but the rotational inertia and the torque/speed response of the wheels and tires is a major parameter of the PID control loop.

I would expect the Segway to be squirrely if you change the size or weight of the wheels.

If its just for show, why pay all that money for a functional unit - why not get a Segway mechanical sample (none functional) if it will never be ridden?