They worry that new federal rules will inadvertently disallow the kind of tire monitoring systems they prefer - so-called indirect systems that take advantage of antilock brake hardware already engineered into vehicles.
Much of the tire industry and many safety advocacy groups favor direct systems, which require an electronic sensor inside each tire and wheel to gauge air presure.
The National Highway Traffic Safety Administration, facing a congressionally mandated deadline, has completed a final regulation requiring tire pressure monitors in new motor vehicles beginning a year from now.
The rule, still subject to White House review, has not been made public, but those familiar with its contents say it is meant to be technology-neutral. That is, it is designed to allow either the direct systems or the indirect systems, which calculate tire pressure by using the antilock brake technology to count wheel revolutions. When pressure is low, revolutions per minute increase because the wheel is slightly smaller, allowing the antilock devices to measure tire pressure.
Unintended consequencesBut automakers believe some of the fine print - such as a requirement that the pressure in all four tires be monitored simultaneously under all conditions - could make antilock brake-based systems unworkable.
"The structure of the final rule may be such that it in fact mandates direct monitoring systems," said Robert Strassburger, vice president for safety of the Alliance of Automobile Manufacturers.
Not that the automakers are opposed to direct systems, which require an electronic sensing device inside each tire or wheel, but they say indirect systems have important advantages.
The antilock brake-based systems would be less costly and could be installed on more vehicles quickly. This is because only a few small companies make the sensors needed for direct systems, and the demand would be for more than 60 million tires and wheels a year.
And antilock-based systems would be almost as effective as the direct systems, automakers contend.
"It's not clear there is an additional safety benefit going to the more sophisticated system," said Michael Cammisa, director of safety for the Association of International Automobile Manufacturers.
$13 vs. $79Adding monitors to a vehicle engineered for antilock brakes would cost about $13, NHTSA estimates. Installing a direct system would cost about $79 a vehicle, the agency says. The cost issue could be an ace in the hole for automakers.
The person principally responsible for the rule's final review is John Graham, the Bush administration's new regulatory czar in the Office of Management and Budget. As a Harvard University researcher, he was best known for studies of costs and benefits of public policies.
The tire pressure monitoring rule will be the first he will consider that has a direct impact on the auto industry.