The tire makers balked after federal engineers studied two dozen brands of tires, and concluded that 30 percent of tires would fail the stiffer standards.
Tire makers themselves say it's even worse, that 40 percent of car tires and half of all light truck tires would flunk.
"If so many tires that are on the road today wouldn't pass this new standard...then what it says is that the tires aren't very good, that the industry has designed them to the lowest common denominator to the minimum federal standard," said Joan Claybrook of Public Citizen, a former National Highway Traffic Safety Administration chief.
The current tire standards were developed 'way back in 1967, before radial tires, at a time when only half the Interstate system was built, so motorists didn't drive as fast. Congress demanded the upgrade in the so-called TREAD Act of 2000, after Firestone tires were linked to hundreds of injuries and 271 deaths.
Under the new proposal, for the first time, tires would be tested while under-inflated, and after being artificially "aged." They'd be tested at higher speeds — up to 75 mph instead of 50. And tests would last six hours longer than before.
Tire makers agree the standards should be strengthened, but not as much as the government wants.
Their lobby group, the Rubber Manufacturers Association, argues in a 71-page letter that the new proposal is "unwarranted and extreme."
"Their tests do not reflect real world conditions for testing tires," said Daniel Zielinski of the RMA, "nor do they accurately reflect tires' performance today on the road, which is outstanding, and tires are safe."
Automakers also fought the TREAD Act requirement calling for tire inflation monitors in all vehicles. They're already found in some cars like Corvettes.
But the auto industry lobbied for — and won — the option to put in cheaper systems that only measure tire pressure indirectly. Public Citizen now plans to sue to force the government to require better monitors that directly measure all four tires.
Congress originally wanted the new tire standards to be set by the first of June, but with the industry's strong objections, the proposal may be re-worked and there's no firm date as to when the new standards will be final.