Picture it the same as towing towing 4 down w/ the steering wheel tied in center position, because that's "almost" the same thing. And that works too. We did that years ago when many vehicles would not track well. And even tire wear was hardly unnoticeable. The only difference, a rigid frame dolly is more forgiving, in that all of the movement is not restricted to the tires slipping, as in 4 down. W/ the rigid frame dolly, leaving the steering unlocked, everything can move a little, so the whole vehicle/dolly assembly is not completely rigid, as one mite think.
And think about this too ! By Acme using the small diameter tires, the footprint of the small tires on the pavement is smaller, giving less traction, therefore letting them slip over the pavement easier. There was some engineering thought went in to this design. And like the rigid frame idea or not, it does work, and apparently works well.
Having said all that, I would still get a DEMCO,....I used to have one. But it is a heavy dolly, and not cheap.
