Engineering's Great Achievements: The Radial Tire by Amy Pistone
For most people, there is no need to think about tires. Until one goes flat, loftier issues occupy common thought. Yet, progress made in the construction of tires has affected many aspects of daily life. The invention and gradual assimilation of radial tires into the automotive world is one of the greatest contributions of engineering, touching many diverse facets of life.
For years, the best tires available were bias-ply tires - tires in which fibers extend diagonally from one bead (where the tire meets the wheel) to the other.
While these tires were adequate, they were slow to respond to steering. As the tires aged, they began to stretch and would become oblong if left parked too long in one position. In 1955, average tire mileage was around 15,000 miles and the development of the interstate highway system promised a significant decrease due to increased heat generated by travelling at higher speeds. The most notable problem, however, was "squirm," the result of round tires that were incompatible with tread made to match the flat road. Clearly, a new tire was in order.
Yet, when the French company Michelin introduced radial tires in 1949, they were not instantly popular, despite numerous advantages. Radial tires contained fibers extending straight across, from bead to bead, with steel belts running along the tire's circumference. These new tires eliminated the huge problem of squirm by conforming to the road without distortion or deflection. Early radial tires had twice the tread life of bias-ply tires and promised improvements beyond that. In addition, less fuel was required due to lessened tire friction.
Why, then, was the acceptance of radial tires a slow process? American technology was not ready for the technologically advanced tires. Radial tires were remarkably precise, revealing hidden weaknesses in car designs. The rough ride originally attributed to inferior tires was actually due to imperfect cars. The shift to radial tires forced automotive companies to correct such inadequacies. In addition to forcing automotive improvement, radial tires? longer tread life saves millions of dollars in tire replacement, reducing gasoline consumption by minimizing tire friction. Fewer tires means less petroleum use, thus saving resources.
In the end, radial tires demonstrate the finest point of engineering - bettering the human condition. Through a seemingly minor contribution, engineering has minimized resource consumption, instigated the move to safer and cheaper transportation, and achieved something major - making life better for all people.