Somewhere between the early tires forged by wheelwrights and the modern steel-belted radial, everyone’s horseless carriage rode atop bias-ply tires. This week’s film is a dizzying tour of the Brunswick Tire Company’s factory circa 1934, where tires were built and tested by hand under what appear to be fairly dangerous conditions.
It opens on a scene that looks like something out of Brazil: the cords that form the ply stock are drawn from thousands of individual spools poking out from poles at jaunty angles. Some 1800 of these cords will converge and be coated with a rubber compound with high anti-friction properties. The resulting sheet is bias-cut into plies, each of which is placed on a drum to be whisked away to the tire room.