AKRON (July 16, 2001) — Tire testing has come under fire in the wake of the Ford/Firestone recalls dating back to last August, but tire manufacturers claim their techniques are extensive, thorough and accurate.
And in the case of tires bound for original equipment vehicles, auto and tire makers work closely in the testing process to help ensure the tires are as safe as possible for that particular use.
Much of the testing process is done before a tire is even built, said Mike Wischhusen, director of product marketing for Michelin North America Inc. And with today´s advances in software, the engineers can design a tire electronically and put it through an array of tests before the building stage, he said.
The automation of testing also has meant improvements in breadth, speed and accuracy, Mr. Wischhusen said. "The beauty of computer modeling is to get the surprises out of the way," he said. "It gives us the opportunity to go back and change something at the computer model level."
Testing protocol also includes lab testing on all the tire components—including carbon black, oil and wire—again utilizing computer simulation in the effort, said Tom Griffing, national technical service manager for Yokohama Tire Corp. Only after each part meets the specifications for that particular tire is it ready for use, said Rick Brennan, Yokohama director of marketing communications.
Tire testing has two levels, according to Mr. Wischhusen. The first comprises the tests on the tire itself, and the other focuses on testing a vehicle system to see how the tires and other parts interact.
At each level, the process is exhaustive. For example, before a recent Michelin commercial truck tire launch, the company ran 200 million real-world miles on the tires with 20 different fleets nationwide.
Road tests generally can last months, said Fran Brennan, vice president, technical, for Cooper Tire & Rubber Co.
But the collaboration on testing between auto and tire makers doesn´t begin at level two. It starts at the design phase and lasts through final fitment, Mr. Griffing said. The OE manufacturer lays down design and performance criteria and the tire maker works with them so the tire product is the most appropriate for that vehicle, he said.
Testing is a shared responsibility with Michelin and its OE customers as well, Mr. Wischhusen said. When working on a particular vehicle, the auto maker provides specifications for tests and the tire maker tests to those instructions, he said, but there is much combined testing.
There is a trend for customers within the auto industry to rely more on their suppliers for validation, though maybe less so for tires than for other components, Mr. Wischhusen said. The result over the years has been increased involvement for the tire maker and joint testing as the norm.
"We see a bit of both; they do some and we do some," he said. "Their engineers come to us and we go there. Truthfully it is a joint operation between both manufacturers."
When there is a new model of a car, or if there is a specification change on a vehicle, the re-specing is done as a new fitment, Mr. Griffing said.
"A tire model being supplied is specific to a particular vehicle," he said. "If there is a suspension component change, there is a specific change of necessity for the tire as if for a new vehicle."
While most tire companies like to conduct their own testing in-house, some do outsource to independent tire testing firms. Yokohama does it frequently, usually when there are time constraints or there is a need for validate their own results or advertising claims, Mr. Griffing said.
If the company doesn´t have a machine needed to perform a specific test, a third party can help out as well, Rick Brennan said. When the firm does use an outside source, often its engineers go along to watch the process.
Cooper—which doesn´t have any North American OE automotive customers—does all of its post-production testing in-house, Fran Brennan said. Michelin, like Yokohama, may outsource to level its workload or to use capabilities it doesn´t have, but those times are rare, Mr. Wischhusen said. The company does use some independent testers to back claims and outsources some fleet testing for taxis and trucks.
"We take great pride in monitoring tire and vehicle performance and like to keep a close eye on what´s happening," he said.
As for making the final determination on a tire´s readiness for mounting and overall safety, Rick Brennan said it remains a collaborative effort—the tire maker produces the tire based on specifications and its vision, while the auto maker makes the call on the vehicle.
Mr. Wischhusen said the vehicle maker has that ultimate call, though not before the tire maker has given all the input it can.
"Nothing leaves our control until we´re very confident in its performance," he said.