Tires without traditional rubber? A tire expert’s opinion

 

The concept of tires made without rubber from “rubber trees” has been around for many decades. World War II and the potential of no “natural rubber” aka latex from rubber trees became a concern for the Allies. Plantations in Asia were under threat of attack and so were the plantations in West Africa. This spurred the development of “synthetic rubber” made from petroleum products.

Synthetic rubber

Firestone produced the program’s first bale of synthetic rubber on April 26, 1942, followed by Goodyear on May 18, United States Rubber Corporation (aka Uniroyal) on September 4, and Goodrich on November 27. In 1942, these four plants produced 2,241 tons of synthetic rubber. The American Chemical Society has a booklet on “The United States Synthetic Rubber Program, 1939-1945” if you want to learn more about the joint war effort.

Following the war, various tire and rubber companies expanded their work on developing “synthetic rubber” made from petroleum and many of today’s passenger and light truck tires are made with up to 100% synthetic rubber. Some of the properties used in mining, off-road, and heavy truck tires including sizes that might be used in a Class-A RV, typically require about 65 percent natural rubber and 35 percent synthetic rubber, as some properties such as cut resistances of natural rubber have not been completely matched by synthetic rubber.

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Race tires from guayule desert shrub

Last year Bridgestone Americas (Bridgestone) celebrated its first-year milestone of using Firestone Firehawk race tires with sidewalls made of natural rubber derived from the guayule (pronounced why-YOU-lee) desert shrub, grown in America’s Desert Southwest.

These tires are built in Firestone’s race tire facility in Akron, Ohio. Firestone has been working on the project of using guayule latex in tires for many years and, according to this Release, it looks like there have been some breakthroughs as Firestone has been using guayule latex for the sidewall rubber on its Indianapolis tires.

 

Does this mean that your RV tires might soon be made of guayule latex? Well, I would not hold my breath for a few different reasons. Volume production would require hundreds if not thousands of acres of guayule to be cultivated and grown to maturity. The use in Indianapolis tires is clearly a “Demonstration Project” and low cost is not a high priority.

Will Bridgestone enter the RV tire market?

Finally, I have not heard of any interest on Bridgestone’s part to enter the RV market, especially for ST-type tires. While currently Bridgestone and Firestone’s tires are available in LT and Class A sizes, I see little reason for the company to push to expand in the RV market as long as the majority of the tires are being overloaded and/or underinflated by the users.

While I have no current knowledge of the status of the program or what the plans are to expand the evaluation beyond Indianapolis race tires, if and when Bridgestone is ready and I hear anything more about guayule latex, I will let you know with an article here.