Balloon Tires at the Speedway

By Sigur Whitaker
 
One of the objectives of the founders of the Indianapolis Motor Speedway was as a test track so manufacturers could test their product. Over the years, there were multiple innovations which debuted at the track, one of which was the balloon tire, introduced by Firestone at the 1925 Indianapolis 500. It changed tire production throughout the United States.  
 
Until that point, automobile tires were based upon the bicycle tire. They were narrow and experienced frequent failures.
 
Balloon tires, an outgrowth of World War I, were first used on airplanes. Pilots were unable to make a safe landing on rough ground at high speed. The tire diameter was enlarged and its strength increased so at low inflation were able to stand the pressure of landing on rough terrain. Pilots were then able to land a plane at 60 mph.
 
What made the balloon tire possible was Firestone's development of the gum-dipping process in 1920. The process began with a white milky liquid collected from rubber trees grown in the Far East and Firestone’s rubber plantations in Liberia. They mixed the crude rubber with pigments and chemicals.  Cotton, shipped to the Firestone Cord Fabric Mills with a capacity of 45 million pounds per year located in New Bedford, Massachusetts, was spun into cotton cords. In the gum-dipping process, Firestone added eight extra pounds of rubber to every 100 pounds of high-stretch cord, coating every fiber in every cord. This reduced internal friction and heat and increased the strength of the tires. After the cords dried, they were pressed on both sides in a process called “calendaring.” The rubber was then cut on the bias to the proper width for the tire. The tire was built by machine. Firestone touted that gum-dipping made the tires stronger and more resilient and that internal wear was practically eliminated.
 
Tommy Milton won the Indianapolis 500 in 1923 in an H.C.S. Special using Firestone gum-dipped cords at an average speed of 90.95 mph. Additionally, the next three finishers in the race had Firestone gum-dipped tires. A Firestone advertisement touted, “It was a contest of driving skill, a competition of automotive science and a ‘Battle of Tires.’ Around this sand-surfaced brick oval, Firestone Gum-Dipped Cords swept through to victory. The grinding wear, the scorching heat, the terrific pace were conditions that only Gum-Dipped Cords and scientifically compounded tread could subside.”
 
Firestone developed the first low-pressure balloon tire in April 1922. It was made possible by using the gum-dipping process. Firestone ads touted “Firestone Balloons give such unheard of mileage, making them the most economical tires to use with the added features of safety and comfort.”
 
Firestone introduced the balloon tire at the Indiana State Fair in 1923 as part of the Cole Motor Car Company exhibit. In September 1923, Indianapolis based Cole Motor was the first large scale automobile manufacturer to adopt balloon tires as optional equipment on all their models except for the Volante where they were standard equipment.
 
Joseph Cole, president of Cole Motor explained the decision, “Before adopting the balloon tires, we made the most thorough investigation, including actual road tests aggregating thousands and thousands of miles—as did also the Firestone Rubber and Tire Company. We find that balloon tires give an improved degree of riding comfort that you never conceived possible, softness and smoothness even over the roughest roads obtained in no other way. They give you double the brake efficiency without locking the front wheels or endangering the lives of your passengers. They greatly reduce the likelihood of skidding—another great safety factory.”
 
Peter De Paolo established a new speed record of 101.13 mph to win the 1925 Indianapolis 500. During the race, one lap was over 106 mph. It was the first time balloon tires had been used in the Indianapolis 500. The top 10 finishers were all using Firestone Balloon tires. One of the tires was put on display at Firestone’s Indianapolis branch.
 
Firestone produced a booklet “How Firestone Gum-dipped Tires are Made” for their exhibit at the 1933 World’s Fair in Chicago to explain the process.