WASHINGTON, D.C.(Sept. 7, 2001)—Tire manufacturers and at least one dealer organization are weighing in on proposed regulations mandating tire pressure monitoring systems in new passenger vehicles by model year 2004.
The Tire Association of North America (TANA) and the Rubber Manufacturers Association (RMA) have submitted their comments and suggestions after the National Highway Traffic Safety Administration published a notice of proposed rule making on the subject in July.
NHTSA has the task of writing such regulations under provisions of the Transportation Recall Enhancement Accountability and Documentation (TREAD) act passed by Congress last fall.
TANA said it would like NHTSA to assure that all automotive service outlets, not just affiliates of the auto makers, may service such monitoring systems. The Reston, Va.-based trade group, made up primarily of independent tire dealers, wants NHTSA to make certain that vehicle original equipment manufacturers and their wholly owned or endorsed stores not have a monopoly on resetting and servicing tire pressure monitoring systems (TPMS).
The RMA, which represents tire makers, is seeking assurances that monitoring systems will alert drivers when tires are unable to handle a vehicle's load, as well as concise definitions of underinflation. NHTSA's proposed rule calls for systems that warn when tires are either 20 or 25 percent below the auto maker's recommended inflation pressure.
“The tire industry cannot support any TPMS proposal that would permit tires to operate outside of industry standards, without any warning to the driver,” a statement issue by the RMA said. “For NHTSA to arbitrarily determine that tires can be operated at lower pressures…is not appropriate and is counter to the intent of the TREAD act.”
The RMA said the present wording of the NHTSA proposal will result in “negative effects” of significant underinflation. It included with its comments a chart listing 30 vehicle-tire combinations, one-third of which failed to have enough reserve inflation to prevent overloading from occurring with a 20-percent drop in pressure.
TANA, meanwhile, added it is critical for the replacement tire industry that OEMs not be allowed to mandate specific wheel-tire combinations on vehicles, as that would eliminate consumer choice.
TANA recommends the NHTSA proposal be altered to say that “each TPMS be able to meet the requirements of the new standard when any of the vehicle's original tires or rims are replaced with any appropriate optional or replacement tire/rim size(s),” and eliminating the words “recommended for use on the vehicle by the manufacturer.”
TANA also stated that NHTSA's 20- to 25-percent reduced pressure range is too nonspecific in defining underinflation, saying it “oversimplifies tire pressure and the way it affects the safety of a tire.” The association recommends tire inflation levels be studied vehicle-by-vehicle.
The debate over tire inflation standards comes from a dispute last year over a spate of Ford Explorer rollovers. Ford and Firestone disagreed on the minimum psi for Wilderness AT tires on Explorers. Firestone recommended 30 psi, Ford 26.
“It is better to be safe than sorry,” said TANA, which advocates following tire manufacturers' recommended pressure. TANA also supported the RMA's definition of “underinflated,” which defines it as “any pressure below the minimum pressure specified by the tire industry's standard-setting bodies for a vehicle's gross weight rating.”
Regarding the TPMS, themselves, TANA said it supports using direct systems, which can detect loss of air pressure if all four tires lose pressure and which it says are less likely to give false readings of significantly underinflated tires.
TANA also is recommending TPMS's include a temperature compensation requirement for when tires rapidly heat up on the road. It asked NHTSA to require that TPMS measure tire temperature and warn operators when tires are becoming too hot.
TANA also recommends that, if a direct monitoring system standard is chosen, NHTSA require tires or wheels be coded—via a sticker, valve code or other means—so automotive professionals will know a tire has a sensor.