AKRON — Necessity drove Karl-Alfred Grosch to become an expert on the friction and wear properties of tires. He wanted to buy a house.
This year´s Charles Goodyear medalist lived with his wife in a small, expensive apartment in London years ago. They wanted to buy a home in the expanding suburbs of London, and located in one of those towns was what now is the Malaysian Rubber Producers Research Association.
Because of that detour, Grosch went on to become an expert in his field and winner of the ACS Rubber Division´s highest technical award, which he received during the group´s April 29-May 2 spring meeting in Akron. (For coverage of the event, see page 6.)
"The incentive was not the research, but that we had a chance to get a house," Grosch said. "So I thought, ´OK, I´ll do a bit of friction and abrasion for awhile,´ but friction stayed with me the rest of my life."
Grosch was surprised when he learned last year that he won the honor. "I was overjoyed. I never thought about it," he said during an interview at the meeting.
The medalist joined the MRPRA as a laboratory assistant in 1955, while still taking part-time course work in physics, leading to his bachelor´s degree in 1958. He was named the group´s principal scientific officer in 1963.
During his tenure at the association, Grosch assisted Adolph Schallamach-himself a future Goodyear medalist-in his work on abrasion. Grosch found that rolling resistance and grip on dry roads are determined by rubber´s viscoelastic properties, but that the separate cases involved different effective frequencies of deformation, according to his Rubber Division biography.
This explained how tread compounds could give low rolling friction and high friction for traction and braking.
Out into industry
Grosch left the MRPRA in 1969 to join Uniroyal´s European Tire Development Center in Germany as tire evaluation manager. He became development manager for commercial tires in 1975, the post from which he retired in 1988.
He said it was important for him to work in the tire industry, rather than stick with pure research.
"Researchers seem to get a very narrow view of things," Grosch said. "With tire development, you get the full view. The compound is not the only thing, but it´s an important aspect. You can estimate much better the importance of various factors because you have the broad picture."
That is particularly true with truck tire development, which he said is a much more difficult task than designing car tires. Grosch said that 80 percent of passenger tires really are treated as commodities by the market, whereas commercial tires truly are industrial products.
"(Truck tires) are judged by everybody who uses them," he said. "So if there is the slightest defect in a commercial tire, you´re going to hear about it."
Tires have seen continuous improvements over the past 60-70 years, he said, to the point where commercial tires now have a safe life of roughly 150,000 to 200,000 miles with retreading. And on the car tire side, there has been a whole set of developments not related to compounds, covering such areas as tread pattern, and balance between traction and noise.
"These are things a generation ago people dreamed of," Grosch said. "It´s always a whole package of developments that run parallel."
Back to research
Following his retirement from Uniroyal, he decided to resume the research he had left years earlier at the MRPRA. "I felt now with the practical experience as tire evaluation and development manager that I could make a contribution to compound properties using my experience with Schallamach," he said.
He built a small prototype machine that developed into the LAT 100 laboratory friction and abrasion test equipment, still marketed by VMI Holland B.V. Grosch developed LAT 100 test programs for wet traction, friction on ice, and abrasion over a wide range of severities.
What makes the LAT 100 stand out, he said, is that it simulates road conditions so tire makers can use the equipment to develop new tread compounds. "I actually defined what road test conditions were, and what are the most important factors that impact a road test: speed, severity, wind, load and other things," he said.
What lies ahead
Grosch, who also previously won the Colwyn Medal from the British Institute of Materials, said he will stick mainly to the background on theoretical discussions, but keep an eye on things. He plans to return to the states to give a paper on friction at the Rubber Division´s meeting this fall in Cleveland.
"I´ve done what I could do," he said. "If I could have done better on it I just don´t know. I never thought it was revolutionary at the time."
But he does see areas for the next generation of scientists to focus on. In traction, he said there are a number of opportunities to find theories. Grosch challenges the young scientists not to look at the road, but at the full data of results available to see if their theories match up.
He warns, however, that the scientists must not fall into the trap of developing a theory and blindly sticking to it.
"You have to look at the whole body of data that we have available," Grosch said. "If you can match all the data, then you have been successful and perhaps with that theory you can develop new ideas to go on."
He sees room for more basic research on silica. While the behavior enhancements silica provides have been documented, it´s not yet clear why silica behaves the way it does.
There also will be continued emphasis on low rolling resistance in tires, but that can´t come at the cost of safety, Grosch said. "Safety and energy savings have to be matched somehow."