Jeeps rode on synthetic rubber tires. Tanks rolled on synthetic rubber treads, and they rolled much farther than German panzers, whose inferior treads grew brittle and cracked in the cold. (“The Germans apparently had not controlled the distribution of styrene,” one U.S. chemist clucked.) By the war’s end, nearly nine in ten pounds of U.S. rubber were factory-made, mostly from oil. This was, wrote an awed observer, “one of the most remarkable industrial achievements of all time.”
