The Transportation Safety Enhancement, Accountability and Documentation (TREAD) Act has been the big news in the tire industry for the past four years and is likely to remain that way for at least four more, according to speakers at the Clemson Tire Industry Conference, March 10-12 in Hilton Head.
``Before 2000, tires were not a big target on NHTSA's radar screen,'' said Claude Harris, director of the Office of Crash Avoidance Standards for the National Highway Traffic Safety Administration (NHTSA).
Even today, tires can't be considered a major safety problem by any means, Mr. Harris said. Data the agency compiled in preparing its TREAD Act-mandated tire performance standards show that tire-related accidents cause about 400 highway deaths annually, out of more than 40,000 highway deaths by all causes and many millions of tires on the road. Furthermore, overloading and underinflation are more likely to cause those deaths than actual defects.
Nevertheless, NHTSA had very little time to develop those standards, thanks to deadlines mandated in the TREAD Act.
``We had to determine reasonable criteria for endurance, and we didn't have enough time to complete those efforts,'' he said.
The tire performance rule promulgated June 26, 2003, covers tires on all vehicles less than 10,000 pounds, except motorcycles and low-speed vehicles, Mr. Harris noted. Its effective date is June 1, 2007.
While the agency deferred action on developing a tire-aging test and upgrading existing strength and bead unseating tests, it still received nine petitions for reconsideration on the performance rule, Mr. Harris said.
These mostly concerned exemptions for specialty tires-whose makers fear they may be forced to curtail or even cease manufacturing-and tread chunking, a rare occurrence in light truck and snow tires but one which their manufacturers insist will be common in the new NHTSA tests for them.
There are also 14 petitions for reconsideration of the tire-labeling rule, and the agency expects to respond to them soon, Mr. Harris said. For tire manufacturers, the major problem with the rule is the requirement to mold the tire identification number on both sides of the tire, which they claim is both dangerous to workers and economically infeasible.
Also, NHTSA is working on a proposed new tire pressure monitoring system rule to replace the one the U.S. Court of Appeals for the Second Circuit overturned in August 2003. The new rule-which supposedly will rely, as the court directed, on devices that record tire pressure directly-should be out late this year, Mr. Harris said.
Yet another TREAD Act-related project requires taking another look at the long-established Uniform Tire Quality Grading System. UTQGS has been in place for more than 20 years, Mr. Harris noted, and was based on the old tire performance standards issued in 1968.
``We have to upgrade the (UTQG) requirements to be as useful to consumers as possible,'' he said. ``We have research progressing now to address these questions, and we will make some decisions in the near future. Our basic question is how to make the UTQG information more consumer-friendly.''
The Rubber Manufacturers Association's petition on tire pressure reserve requirements for tires was addressed in a separate speech by another NHTSA official-Ezana Wondimneh, safety standard engineer in the Office of Crash Avoidance Standards.
What the RMA wants to ensure, Mr. Wondimneh noted, is sufficient tire pressure to support a vehicle's maximum load when the low-pressure warning of a tire pressure monitoring system activates. While a 1981 NHTSA study concluded that no correlation exists between pressure reserves and tire failures, the RMA petition persuaded the agency to commission a new study in 2003.
To expedite the process, NHTSA issued an emergency special order for information to tire and vehicle manufacturers in January 2003. The order requested data on all light vehicles manufactured between 1996 and 2002, Mr. Wondimneh said, including original equipment tire failure claims and vehicle production data describing every unique vehicle-tire combination manufactured for sale in the U.S. NHTSA promised to treat all data as confidential, he added.
``It was a tough task to match the data from different manufacturers because each company has its own idiosyncratic terminology,'' Mr. Wondimneh said. Nevertheless, he added, the agency expects to publish its findings on tire reserve pressure this fall.
Meanwhile, the RMA is concerned that the NHTSA reauthorization process this year could deliver the agency and the tire industry more mandates on such issues as tire aging, according to Ann Wilson, RMA senior vice president. The association is already working with NHTSA and the American Society for Testing and Materials on developing a tire aging test, she noted, but provisions in the Senate NHTSA reauthorization bill could accelerate that effort unreasonably.
``We're not opposed to the Senate language, but we're concerned that the new tests be based on sound science and that NHTSA has sufficient time to research this issue,'' Ms. Wilson said.
The British Rubber Manufacturers Association, she noted, has released guidelines recommending that all tires be sold within six years of the date of manufacture and removed from service within 10 years. ``This is an issue we need to continue to work on,'' she said. ``We're working with European tire groups to see what information they have.''
Faced with four recalls of tires on its vehicles in five years, Ford Motor Co. decided to develop and perform its own laboratory tests to measure the effects of tire aging, according to John M. Baldwin, a polymer science technical specialist at Ford.
``We tried to look for aging standards for tires and couldn't find any,'' Mr. Baldwin said. What Ford has been trying to do, he added, is determine whether a new tire can be artificially aged, duplicating the actual mechanism of chemical and mechanical aging in field tires.
Ford's data on the performance of recalled Firestone Wilderness AT tires suggest tire aging is an important thing to quantify, according to Mr. Baldwin. ``If you look at the first two years of service for those tires, there essentially were no reports of failure,'' he said. ``It took two years for something to happen. Then, when you look at two vs. four years of service, peel strength had dropped 50 to 75 percent in the field. Obviously, the rubber's changing.''
Currently, Mr. Baldwin's research is closely concerned with belt skim/wedge rubber and focused on static, chemical aging in full-sized spare tires. ``Spares that haven't been used look very similar to spares that have been on the road,'' he said.
To date, Ford has determined that the chemical aging of a tire can be accelerated through prolonged heating in an oven, Mr. Baldwin said.