Michelin Blows Away Myths and Misconceptions About Tire Pressure; What You Don't Know Will Surprise You

LAURENS, S.C., May 3 -- As part of South Carolina State "Tire Safety Awareness Day," Michelin did more than just extol the virtues of tire maintenance. At its proving grounds in Laurens, S.C., the international tire maker put on some dramatic demonstrations using a very mundane medium: Air! The Laurens Proving Grounds often plays host to some of the world's most expert test drivers, but today the experts behind the wheel were police, troopers, administrators, even journalists who learned first-hand the critical role tire air pressure plays in braking and vehicle handling.

The National Highway Transportation Safety Administration estimates that nearly half of all passenger cars on the road have at least one tire under- inflated by 20 percent. That means, if the vehicle placard indicates the correct pressure is 32 psi (pounds per square inch of pressure) a 20 percent reduction would drop the pressure to about 26 psi. "That seemingly small difference can mean the margin between control and out of control for the average driver," said Mac Demere, test driver at the proving grounds, "especially on wet road conditions."

To illustrate, Michelin set up a tire evaluation test for invitees from the State Highway Department, local sheriffs and deputies from Anderson, Greenville, Lexington, Richland and Spartanburg, members of the South Carolina Public Safety Commission and members of the media. The test required the driver to accelerate to 50 miles per hour and then stop as quickly as possible on a wet surface. First the test was run with tires at correct inflation pressure, then at inflation pressures 20 percent below the vehicle manufacturers recommendation.

"With the correct pressure, the tires are in contact with the road, evacuating water through the tread grooves and transmitting the braking force that will bring the car to a halt," said Demere. "But when you lower the pressure by 20 percent, the center of the tread is no longer making contact with the road. Basically, your tires are riding on water and it takes a greater distance to bring the car to a stop." For some participants, that increased distance was as much as 7 feet, clearly illustrating the reduced braking power of under inflated tires.

The same is true in cornering. The test required drivers to maintain a steady speed of 50 miles per hour while driving around a gentle curve covered with a puddle of water, simulating highway conditions after a thunderstorm. Drivers had no problem maintaining vehicle control when tire pressures were at the correct setting, but hydroplaned out of control when the pressures were dropped by 20 percent.

"We believe these tests demonstrate in graphic terms the need for proper monitoring of tire air pressure," said Nan Banks, Michelin's director of public relations. "In particular, we much prefer devices that alert drivers whenever their tire pressures drop below the vehicle manufacturer's recommended settings."

For more information on tire safety and the importance of tire inflation pressures and other tire maintenance, visit www.michelinman.com and click on "care and safety."

Michelin manufactures and sells tires for every type of vehicle, including airplanes, automobiles, bicycles, earthmovers, farm equipment, heavy-duty trucks, motorcycles and the space shuttle. The company also publishes travel guides, maps and atlases covering Europe, Asia, Africa and North America. Headquartered in Greenville, S.C., Michelin North America, Inc. (www.michelin.com) employs 26,500 and operates 23 plants in 19 locations.