WASHINGTON—Tougher endurance tests for tires used on heavy trucks, and a new high-speed test for heavy radial truck and bus tires are among the highlights of a proposed federal standard for truck, bus and commercial tires.
Nearly 10 years in the making, the proposed revision to Federal Motor Vehicle Safety Standard 119, issued Sept. 29, didn't have any surprises for the tire industry.
“What they put out has been fairly consistent with what they discussed with us,” said a spokesman for the Rubber Manufacturers Association. “But there is not much information on how it will affect safety, because there has been no real designation of truck tires as a safety problem.
“We hope the final rule will be efficient and not terribly costly, and have some benefit,” the RMA spokesman said.
The proposed regulation, published in the Federal Register by the National Highway Traffic Safety Administration, includes a more stringent endurance test for tires intended for motor vehicles with a gross vehicle weight rating of more than 10,000 pounds.
It also calls for a new high-speed test for heavy radial truck and bus tires that have load range ratings of F, G, H, J or L and aren't designated for speed-restricted service.
If it becomes final in its present form, the proposal also would require all truck, bus and commercial tires to have their maximum speed ratings labeled on their sidewalls.
Paul Fiore, director of government and business relations for the Tire Industry Association, said TIA has found nothing objectionable in its first reading of the proposal.
“It's been 37 years since this regulation was first written, so it would be foolish not to acknowledge that the requirements on commercial tires have changed,” Fiore said.
What the rule will do
The rewrite of FMVSS 119 was mandated by the Transportation Recall Enhancement, Accountability and Documentation Act passed by Congress in 2000.
Despite the broad sweep of the TREAD Act, with its massive revisions of auto safety regulations, tires were a particular focus of the bill.
The TREAD Act was motivated by the Ford/Firestone rollover scandal, which resulted in Bridgestone/Firestone recalling some 6.5 million tires that had been original equipment on the Ford Explorer.
Among other things, the TREAD Act mandated new safety standards for tires, including the development of stringent new tests adequate to measure the performance of a new generation of tires.
FMVSS 139—replacing FMVSS 109, which had been the safety standard for passenger tires since 1966—was promulgated as a final rule in June 2003.
The TREAD Act mandated the revision of FMVSS 119 by June 2002. However, in the preamble to the FMVSS 139 final rule, NHTSA said it needed more time to study and analyze the technical issues specific to medium and heavy vehicle tires before writing a new FMVSS 119.
NHTSA begins its new proposal by pointing out FMVSS 119 was developed in 1973 and has not been revised since then.
“We have commenced this rulemaking primarily because we have tentatively determined that the FMVSS 119 performance tests … should be updated to reflect the increased operational speeds and duration of truck tires in commercial service,” the agency said. It said it tentatively determined the proposal would benefit highway safety, but offered no quantification.
Current endurance testing under FMVSS 119 applies to truck tires with load ranges F through N that are not for speed-restricted service, NHTSA said in the proposal.
The new, recommended endurance test would upgrade the parameters for non-speed-restricted radial truck tires with load ranges of F, G, H, J or L, the agency said.
All other tires covered by FMVSS 119—including bias-ply tires, tires in other load ranges, speed-restricted tires and motorcycle tires—would have unchanged endurance tests.
Among other things, the enhanced endurance test would have a test speed of 50 mph, up from the current 40 mph, and would require test tires to be at 80 percent of sidewall-labeled inflation, instead of fully inflated as currently required.
The FMVSS 119 high-speed test, which now applies only to motorcycle tires and tires with rim diameters of 14.5 inches or below, would be extended to the same truck tires that would be covered under the enhanced endurance test, NHTSA said.
Under the proposed rule, the high-speed test would be initiated after a two-hour break-in at 50 mph, with 85 percent of maximum load rating and 90-percent inflation, the agency said.
The proposed rule notes a number of suggestions made by the RMA for the high-speed test. NHTSA incorporated some of the association's recommendations, such as a stepped-up speed test with three 30-minute steps using test speeds indexed to the corresponding speed rating of the tire.
However, the agency rejected other RMA recommendations, such as the removal of the two-hour break-in step. NHTSA asked for comments specific to these decisions.
Nov. 29 is the deadline for comments.