Tires have not always been those long lasting, comfy riding, high grip units we are used to. Not so long ago, vehicle tires were an entirely different looking, and performing, piece of technology.
While the wheel is positively ancient, at around 5,000 years old, the tire is much newer, at about 150 years old. Horse-drawn carriages of the time used hand-crafted wooden wheels with a steel band as the tire. This band was called a “tie”, and may have led to the word “tire.” The tire was heated in a forge, put on the soaked wheel, and quenched in cold water, contracting the steel tire to the wheel. Steel was used for several reasons. First, it was durable enough for the demanding ride, and blacksmiths were readily available in even small towns to repair any damage. Ride comfort was nonexistent, but a carriage’s leaf spring usually absorbed most of the jolts.
While air filled (pneumatic) tires were available from the mid-1800s, they were unreliable and therefore not common. Solid rubber tires were much stronger, and became the tire of choice. Towards the later 1800s, there was a huge boom in bicycling, and a larger demand for tires. Companies responded by taking another look at the air-filled tire, and by 1890, pneumatic was the dominant choice. These early air filled tires provided a soft ride, but lacked durability. The common process was taking natural rubber from a tree, refining it, adding some sulfur and zinc for strength, and pouring into a mold and heating (vulcanizing).
Karl Benz developed several new technologies while on his way to patenting the first automobile in 1886, including a steel wheel with solid rubber tire. This quickly fell to the wayside, as manufacturers added carbon black early in the 20th century. Carbon black is a result of an incomplete combustion of oil, and adds strength and durability when added to the mix of tire ingredients, helping create durable pneumatic tires.
Around this time, ‘teens and twenties, manufacturers were essentially making two tires, one inside the other. The inner tube was a soft rubber that held the air. The outer bias-ply tire had the tread for grip and durability, and the tube for a soft ride. The bias-ply referred to the construction method. Layers of tough fabric cords, called ply, were angled at 40 degrees and put down in several layers, adding strength to the design. This would be the dominant street tire through the end of World War II.
In the 1940’s, due to scarce resources, European manufacturers started building radial tires. This design has the cords at 90 degree angles, backed by a steel belt. While radials were heavier and had a stiffer ride, they achieved a higher fuel efficiency. American buyers snubbed these rough riding tires, until the gas crisis of the 1970s. The switch was so dramatic, by the mid-80s, all cars in the United States came with radials.
Manufacturers responded to demands for safety in the 1980s and ‘90s, developing water-wicking tread designs that prevent hydroplaning. Asymmetrical designs increased traction on high performance tires as the horsepower was returned.
Americans were hit with another gas shock in the mid-2000s, leaving gas prices permanently hovering over $3.00 a gallon. Manufacturers developed low rolling resistance technologies to reduce friction between the tire and road, while still making them durable and safe.
photo courtesy Harry Rowed. National Film Board of Canada. Photothèque. Library and Archives Canada /