November 1, 2008 Ergonomists found that when replacing a vehicle's tires, the two newest tires should be placed in the rear in order to avoid oversteer and hydroplaning. Oversteer is when the rear tires slip out, creating a sharper turn than intended, which causes the car to lose traction. If the front tires lose control on a wet road, the driver should be able to react to hydroplaning more effectively.
The next time someone installs tires on your vehicle, watch closely. The method they choose could steer you into a dangerous situation. Researchers have found three out of four people don't know where two new tires should be placed on a vehicle. It's a question of safety that even sparks debate among tire experts.
Larry Augustine knows a lot about tires. He installs nearly 30 every day, which adds up to more than 7,000 tires ever year. He's often asked to put two tires on at a time.
"If it's a front-wheel-drive, we usually put them on the front of the car," Augustine said. "That's where all of the action is."
A lot of his customers, like minivan owner Ted Wernikoff, follow his advice.
"I was told they should be put on the front, and until I'm told differently, I will probably do that," said Wernikoff.
Michael Wogalter, Ph.D., an ergonomist at North Carolina State University in Raleigh, N.C., knows exactly where the tires should go -- and it's not on the front.
"The main reason for putting them on the rear as opposed to the front is because of the potential of oversteer and hydroplaning situations," said Dr. Wogalter. "Oversteer literally means the rear tires slipping out and is more of a sharper turn than is intended."
That means if the front tires lose control on a wet road, the driver should be able to feel the hydroplane more and may be able to react.
"In the other situation -- when the rear tires slip -- it's much more difficult to control," Dr. Wogalter said. "Sometimes, it's impossible to control." The idea of losing control on the road is enough to change Wernikoff's way of thinking.
"I have no reason to argue with the latest research," Wernikoff said. "If that's the way they found from the studies that it should be done, I will do it that way." Thanks to ergonomics, you and your family can have a safer ride.
WHY PLACE NEW TIRES ON REAR WHEELS? When people want to replace two out of the four tires on their vehicles, often they don't know where the tires should be placed. Testing has shown that with very few exceptions, the new tires should be placed on the rear wheels. This protects drivers from a dangerous condition called oversteer.
WHAT IS OVERSTEER? When the rear wheels of a vehicle lose their traction and slide to the outside of a turn, they slip out of their track behind the front wheel. Oversteer is event that occurs prior to many rollovers and single vehicle loss-of-control accidents. It can cause the driver to lose control, and the vehicle to spin out. It usually happens while traveling around a corner, and is an important issue for race car drivers.
The Human Factors and Ergonomics Society contributed to the information contained in the TV portion of this report.