The Rubber Manufacturers Association (RMA) states that the new federal regulation mandated by the Transportation Recall Enhancement, Accountability and Documantation (TREAD) Act concerning tire pressure monitoring devices on all passenger vehicles and light trucks by 2004 may have safety implications by allowing some tires to operate at inflation pressures that are insufficient to carry the vehicle.
"Safety should be the overriding priority for this regulation," says Donald Shea, RMA president and CEO. "A regulation that arbitrarily allows tires to be operated at inflation pressures that are insufficient to carry a vehicle load is inappropriate and counter to the intent of the TREAD Act which Congress enacted to promote tire safety," says Shea. "The tire industry cannot support a tire pressure monitoring system rule that would permit tires to operate outside of industry standards without any warning to the driver."
In October, the RMA had urged the National Highway Traffic Safety Administration (NHTSA) to adopt a requirement that a tire for a particular vehicle must have sufficient inflation and load reserve. A mandated "reserve pressure" would allow a tire pressure monitoring system to alert motorists when the vehicle load exceeds the design specification of the tire, the RMA says.
To make sure a tire has sufficient reserve, vehicle manufacturers -- which establish the recommended inflation pressures for tires -- could increase the recommended inflation pressure in their vehicles' tires or use a different size tire for a particular vehicle, the RMA notes.
Last year, the RMA gave NHTSA a chart listing 30 examples of vehicle tire combinations. While two-thirds of those combinations exceeded a 20% reserve pressure, 33% did not have a sufficient reserve inflation pressure to permit a 20% drop in recommended pressure without significant underinflation occuring, according to tire industry standard-setting bodies.