NHTSA Seeks Stricter Rules for Truck Tire Performance

This story appears in the Oct. 11 print edition of Transport Topics.

For the first time in 37 years, federal regulators are proposing tougher standards for truck tire performance, including new speed tests.

The National Highway Traffic Safety Administration announced that it intends to create more stringent tire inflation and load tests and add a requirement to label tires with their load specifications.

Until the new regulations become final, tire safety will be regulated by Federal Motor Vehicle Safety Standard No. 119, which was written in 1973. At that time, the maximum allowable national truck weight was 73,280 pounds and the national speed limit was 55 mph.

“This notice of proposed rulemaking has a beneficial effect on safety, in that it would ensure greater tire durability as tires are held to more stringent standards than currently required,” NHTSA said in a Sept. 29 Federal Register notice.

Comments are due before Nov. 29 at the agency, which will study them before issuing a final rule. There is no specified time period for agencies to study federal rules.

The upgraded tests are focused on five categories of tires — F, G, H, J and L — that are used on vehicles with gross weight of more than 10,000 pounds. The letters stand for their load range, which is the maximum weight the tires can support at a specified inflation level. Heavy trucks primarily use G and H load-range tires.

The speed, performance under load and inflation pressure tests performed by NHTSA would be toughened.

Tires in all five load ranges would be tested at 50 mph. In the current tests, some tires are tested at speeds between 30 mph and 40 mph.

The proposed new test would measure tire performance at a higher percentage of the maximum weight they are designed to carry. The new test would be done in stages at 85%, 90% and 100% of the maximum load. The current test is done in stages at 66%, 84% and 101% of the maximum load.

The test of tire performance based on inflation is being toughened by reducing the pressure to 80% of the recommended pressure from 100% in the current test. The 80% inflation level is a tougher standard because the tire has to meet increased performance requirements even when it’s not fully inflated.

The new high-speed test for truck tires would be done at 85% of maximum load and 90% of maximum inflation pressure at speeds up to 81 miles per hour.

Industry reaction to the new rules proposal was supportive but cautious.

“Our members are still reviewing the proposal,” said Dan Zielinski, a spokesman for the Rubber Manufacturers Association, which represents tire makers such as Bridgestone, Goodyear Tire & Rubber Co. and Michelin North America. “Broadly speaking, our members support test standards that are cost-effective, deliver measurable safety benefits and reflect real-world conditions under which tires operate.”

“Though the proposed upgrades to commercial truck tire standards are not final, we are confident that our products will continue to deliver a high level of performance in real-world conditions and comply with whatever rules may be adopted,” said Ed Markey, a spokesman for Goodyear, Akron, Ohio.

“This is pretty much what we expected,” said Paul Fiore, director of government and business relations for the Tire Industry Association, a trade group that represents retail stores. “There is common sense — going into this with more speed rating and load testing — but we are withholding final judgment until our technical staff reads the details.”

The requirement to toughen truck tire standards dates to 2000, when it was mandated by the Transportation Recall Enhancement, Accountability and Documentation Act. That law was sparked by the deaths of about 300 people in rollover accidents, primarily involving sport utility vehicles whose tires had manufacturing flaws.

NHTSA decided when it was writing tire rules first to do the regulations for vehicles weighing less than 10,000 pounds, which were issued in 2003, before tackling truck tire standards. Since then, the agency has consulted with trade groups and tested performance of sample tires before issuing its proposal.

“We believe that most tire manufacturers will be able to meet [standards] without substantial difficulty,” NHTSA said in the proposed rule, estimating the cost of compliance at $13.3 million.

NHTSA has not yet decided whether M load range tires will have to meet the new standards. Construction, logging and other vehicles often use those tires in both on-road and off-road service.

The N load range tires won’t have to meet the new standards because they typically are used in low-speed, off-highway service, NHTSA said.