According to the Rubber Manufacturers Association (RMA), only 9-percent of the vehicles on the road have four properly-inflated tires and 11-percent have at least one bald tire. Those are pretty scary numbers, and they were recently validated when Cooper Tire and Good Morning America went to a large parking area and checked the tires on workers' vehicles. Their findings were nearly identical to the RMA's.
It's easy to monitor your tires:
Check tire pressures monthly. Tires should be inflated according to the manufacturer's recommendations. Tire pressure specs can be found on a sticker on the door or in the glove box; the number is also in your owner's manual.
Never set pressure to match the number listed on a tire's sidewall -- that number is the maximum safe inflation pressure for the tire and has nothing to do with the recommendation for your vehicle.
- If you find one tire that is lower than the others, have it checked for a puncture.
- Keep in mind that it's normal for tires to loose some air pressure, especially when temperatures change.
- Manufacturers recommend checking tire pressures when the tires are cold. If you have to check and air them hot, it's probably safe to go with one or two pounds over the cold recommendation.
Over and Under-Inflated Tires
- Over-inflated tires can result in premature wear, a harsh ride and poor handling.
- Under-inflated tires can cause poor handling, premature wear, increased fuel consumption and tire overheating.
- Tire overheating can cause an internal breakdown of the tire resulting in tread separation or sidewall blowout.
Check for Tire WearTire wear should be checked every time you check tire pressures. Watch for these trends:
- A tire that is more worn on either the inside edge or outside edge can be an indication of an alignment problem.
- Wear on both the inside and outside edges usually indicates low tire pressure.
- Wear in the center of the tread usually results from an overinflated tire.
If tire wear looks even, use a depth gauge to check the tread depth at three points around the tire. The tread on a new car tire usually measures about 11/32", while tread on a new truck tire can be as deep as 15/32". All tires are considered worn out at 2/32". Most, if not all, tires have wear bars molded into the tread area; when these bars are flush with the tread, the tire is at 2/32".
You can use a penny to do a quick thread-wear check. Insert the penny into the tread with the top of Lincoln's head pointing down. If you can see the top of his head, the tire is worn out.
Just because a tire isn't technically considered "worn out" until it's tread measures 2/32" doesn't mean it is "good" at 3/32". You'll discover that stopping distance is greatly increased, cornering grip is reduced and ride comfort deteriorates as a tire wears.
Worn Tires on Wet RoadsDriving on wet roads with worn tires can be very dangerous because the tread is not deep enough to channel water out. Hydroplaning is the result -- the tire rides on top of the water and all traction is lost.
I experienced hydroplaning first-hand during an event at the Cooper Tire Vehicle Testing Facility, located not too far south of San Antonio, Texas. Cooper laid out a course with cones and ran water across the track. First, we drove the course in a car with tire tread that was worn down to 4/32", and then followed-up by switching to a car running on like-new tires. The difference was amazing. On worn tires, we had to slow dramatically in order to control the car in curves; the new tires gripped the wet pavement and cornered easily, with no slide.
Even though our worn tires had tread that measured double the minimum depth, acceleration, stopping and especially cornering were dramatically affected. More people would replace their tires sooner if they could experience the same test in a controlled environment.
Take a few minutes today to check your tires, continue to check them regularly, and pass on the recommendation to your friends. We'd all feel safer knowing that the vehicle coming toward us on the highway has properly inflated tires with good tread.