By NANCY TULLIS
VINDICATOR SALEM BUREAU
NORTH LIMA -- Twist. Pull. Squish.
Since 1932, the Firestone Test Center here has been dedicated to tire torture.
"It's the only tire test center anywhere that is totally dedicated to agriculture and logging tires," said Ken Medvec, manager here for 25 years.
Harvey S. Firestone grew up on a farm nearby at the intersection of state Route 14 and Creek Road. He started the Firestone Tire and Rubber Co. in 1900, and in 1932 introduced the first rubber tire for farm tractors.
For two decades, the testing was done on the Firestone family's dairy farm. Firestone employed dozens of workers to drive tractors and other equipment in all kinds of conditions to test the company's agriculture tire and its competitors.
In 1952, the company purchased 350 acres of the former Lower farm on Lipply Road and relocated the tire test center to its present location. Medvec said during his first few years as manager, most of the testing was done by workers actually driving the equipment.
Automated advancement: In recent years, however, engineers have developed automated equipment able to test tires 24 hours a day. With the automation, the test center now operates with just four employees.
One of the most visible tests is done on concrete, asphalt and slag tracks on which driverless tractors pulling various farm implements circle endlessly around 5 miles per hour. Medvec said a cable attached to a center post and locked steering keep the tractors on course.
"We used to have people actually driving the tractors, and their biggest challenge was boredom," Medvec said. "One year we had a medical student working the summer here, and he kept falling asleep. The tractor would be circling then all of a sudden it would go off the track."
Firestone and competitors' agriculture and logging tires are tested for endurance and traction, Medvec explained. Engineers interpret the test data, which is used to make design changes.
The company's biggest challenge is keeping up with the evolution of farming and logging, he said.
"The question of what makes the perfect tire is always changing. "We test our competition as well as our own tires, because we want to be better than the competition."
Most of the tests the tires are put through are destructive tests, Medvec said.
"We try to fatigue the tire and do everything we can to make those tires fail. ... The farmers want to know they can drive our tires through a field without a puncture when they run over those inevitable deer antlers.
"Loggers want to know they'll get back home, and won't be stranded in the woods because of a failed tire."
Endurance: Firestone gives an eight-year warranty on its agriculture tires, so testing tire endurance is crucial. Continuous testing over a four-month period, for example, puts a tire through the wear and tear, and exposure to the elements it would experience in a six- to eight-year period in actual use, he said.
In several acres of the test center, corn and other crops are planted, so tires are put to the test in real-life conditions.
Keeping up with changing trends in the agriculture industry, the current challenge is to create a tire that performs well in the field and on the highway, Medvec said.
Farmers tend to be on the highway with tractors and other equipment as they farm land in different areas, he said.
Tire design must also change constantly to meet changes in equipment. Firestone designers, engineers and the test center staff work closely with equipment manufacturers such as John Deere and Case to develop tires that match the capability of the equipment on which they are used, he said.
Goal: Medvec said when Harvey S. Firestone first put rubber tires on tractors in the 1930s, he wanted to make farm work more efficient, and give farmers a more comfortable ride. That's still the test center's goal, he said.
More information about Firestone's agricultural division is available online at www.firestoneag.com.