when the tire hits the other tire on the ramp, it looks very fake. The camera moves out of view just as a tire gets random energy to move up a pretty steep ramp.
"At one point three tyres, amazingly, roll uphill. They do so because inside they have been weighted with bolts and screws which have been positioned with fingertip care so that the slightest kiss of kinetic energy pushes them over, onward and, yes, upward. During the pre-shoot set-ups, film assistants had to tiptoe round the set so as not to disturb the feather-sensitive superstructure of the arranged metalwork. The slightest tremor of an ill-judged hand could have undone hours of work."
