Answer Man

How tires — and the rubber for them — came together

Harvesting rubber in a rubber tree plantation in Thailand.
Harvesting rubber in a rubber tree plantation in Thailand.

Q: At what point did we stop using rubber from the trees in tropical forests for tires? Who thought of this in the first place?

Tom Bellman, of New Athens

A: They always say necessity is the mother of invention. Never was that proverb truer than when Scottish native John Boyd Dunlop made what is regarded as the first practical pneumatic rubber tire in the 1880s.

At the time, Dunlop was running one of Ireland’s most lucrative veterinary practices in Belfast, according to the 1938 book “Wheels of Fortune: A Salute to Pioneers” by Sir Arthur Du Cros. Then, he ran into a family dilemma. His doctor, John Fagan, recommended that Dunlop’s 10-year-old son, Johnnie, get more exercise on his tricycle. But riding a tricycle with unforgiving metal tires on the cobblestone streets of Belfast had the young lad constantly complaining of headaches from the rough ride.

To remedy the situation, Fagan and Dunlop designed the first air-filled tire — a mix of canvas bonded with liquid rubber — to make his son’s riding more pleasant. It led to a patent being granted him on Halloween 1888, although four years later the patent was declared invalid when drawings of a similar tire made by Scot Robert Thomson, of London, in 1847 were discovered. Thomson’s tire, however, was never produced, so it is Dunlop who is credited for “realizing rubber could withstand the wear and tear of being a tire while retaining its resilience,” according to the Hutchinson Dictionary of Scientific Biography.

Considering the name, you’re probably thinking Dunlop immediately started turning out the automobile tires that still bear his name today. Not so. Dunlop’s interest was in bicycles and light vehicles. The company’s first car tire first rolled out in 1900, after the elder Dunlop had retired. By that time, car tires had been marketed for years, starting with another name you’ll surely recognize: In 1895, André Michelin and his brother Edouard, who already had patented a removable bike tire, built their L’Éclair automobile for the Paris-Bordeaux-Paris auto race. It was the first car in the world to sport pneumatic tires, the Michelin corporate website boasts.

Of course, Dunlop, Michelin and all those who came later were merely building on centuries of discoveries. Many historians say rubber may have been first used by the Olmec civilization in Central America, who then handed down its knowledge to the ancient Mayans in about 1500 B.C. It is thought that they boiled latex from the Pará rubber trees to make balls for games. In fact, Christopher Columbus watched the natives of Central and South American play a game called Tlachtlic, a cross between basketball and football, according to the Rubber Manufacturers Association.

But the raw material by itself had few uses because its properties were dictated by the temperature of its surroundings. In the summer, it was soft and sticky, while in the winter it became hard and brittle. Not exactly the stuff you’d want your tires made from. But that all changed one day when a mixture of rubber, white lead and sulfur was accidentally dropped on a hot stove. When it was removed, the material was no longer affected by the temperature but still retained its elasticity.

It was a process called vulcanization, and it was patented by Charles Goodyear in 1844. Finally there was a way to make usable raincoats, overshoes — and tires. Today, there are an estimated 400 tire companies that turn out more than 1 billion tires a year.

But as you suggest, that’s still not the end of the story. In 1876, the English, tired of plodding their way through jungles to secure quality rubber, started planting rubber tree plantations in Southeast Asia and Africa. Today more than 90 percent of the world’s natural rubber comes from Southeast Asia, according to the Rubber Manufacturers Association.

Then, in the 1940s, the United States faced a crisis when we were cut off from virtually all sources of rubber in the Pacific during World War II. That’s when the production of synthetic rubber, first developed by Bayer in Germany in the 1920s, exploded. Before Pearl Harbor, the U.S. was producing only 8,000 tons. By the end of the war, production had skyrocketed to 820,000 tons.

Synthetic rubber is produced by mixing petroleum byproducts. It generally takes about seven gallons of oil to make one tire. Today, about 70 percent of all rubber used is synthetic, according to the rubber association.

But that does not mean the tires on your car are purely synthetic. According to a 2012 article in Road & Track magazine, natural rubber still offers a toughness unmatched by its faux relative. It says a typical passenger car tire is usually about 55 percent synthetic and 45 percent natural. Tires for off-road vehicles may be as much as 80 percent natural.

As a result, companies are looking for new sources of natural rubber as demand for it continues to grow around the world. The hunt is starting to pay dividends. In October 2015, the Bridgestone Corp. announced that it had produced passenger tires with 100 percent of their natural rubber coming from the bark and roots of the guayule, a desert shrub native to the arid regions of the southwestern United States and northern Mexico. The company says it aims to use 100 percent sustainable materials in tires by 2050.

Today’s trivia

Two for one: Why do we call it “rubber”? Why do we call them “tires”?

Answer to Friday’s trivia: It’s now a common joke that the three most important factors determining the desirability of a real estate property are “location, location, location.” But who said it first and when? Many attribute it to English real estate mogul Harold Samuel. But in 1926, the Chicago Tribune ran the first known printed version in this classified ad: “Attention salesmen: location, location, location, close to Rogers Park.” Since the phrase evidently was already likely in common usage, Samuel, who was 14 at the time, played no role in its coinage.

Roger Schlueter: 618-239-2465, @RogerAnswer

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