Tire Information

Updated January 2009

Page: 5 of 6

In this report

Tire Links

This report covers all-season and three-season tires for cars and minivans. Please consult our separate reports on SUV/light truck tires and snow tires for more information on those types of tires.

Tire Recalls

Check your tires' valve stems (the stalks where you check the pressure and top off the air): If the caps say "Dill," you may have defective stems that could lead to a crash. Millions of defective Chinese-made stems were installed in multiple brands of tires sold between November 2006 and July 2007, the National Highway Traffic Safety Administration announced in December 2008. The valves may lack a protective compound, which could lead them to deteriorate, crack, leak and lose pressure. Two separate recalls of the valve stems may affect as many as 30 million tires in North America -- but nobody knows exactly which tires, because the lot numbers on the stems are hidden inside the tires. A website set up to handle the recall, TireValveRecall.net, recommends that owners get a professional inspection, or check their valves themselves by bending them and looking for cracks. Cracked valves covered by the recall will be replaced for free.

Never miss a vehicle safety recall again: You can now sign up to get automatic e-mails or RSS feeds anytime your tires, vehicles or child safety seats are recalled. The National Highway Traffic Safety Administration unveiled its free electronic recall alert system in 2008. Visit SaferCar.gov to sign up.

"Penny test" outdated

The "penny test" is no longer good enough to tell whether your tires have enough tread left, according to The Tire Track and Consumer Reports. For decades, drivers have used it as a rule of thumb: If you can see the top of Lincoln's head when you hold a penny upside down in a tire tread groove, you've got less than 2/32-inch of tread left and it's time to replace your tires. But in July 2007, tests at The Tire Rack showed that on wet pavement, it takes much longer to brake to a stop on tires that are worn so low (see video of panic stop tests here).

In November 2007, Consumer Reports announced it had conducted similar tests that found the same thing. Both organizations now recommend replacing tires with less than 4/32-inch of tread left, visible with a new "quarter test" (your tread should reach to the top of Washington's head).

New fuel economy ratings coming

A new law requires tire makers to start telling consumers how fuel-efficient a tire is. As part of a sweeping energy bill signed into law in December 2007, the National Highway Traffic Safety Administration must develop a system for rating tires' fuel efficiency. Right now, the only fuel efficiency information comes from independent testing organizations, such as Consumer Reports, which test tires' rolling resistance. The NHTSA is supposed to have the new rule in place by the end of 2009, according to news reports. The law also calls for the creation of a nationwide program to educate consumers about tire maintenance, such as proper tire pressure, alignment, rotation and treadwear -- all of which can boost fuel economy, safety and durability.

Find your tire's ratings

The National Highway Traffic Safety Administration currently grades tires in three categories: temperature, traction and treadwear. Find these ratings at SaferCar.gov.

Temperature, or heat resistance, is graded A (highest), B or C (lowest and the minimum performance standard required by federal regulation). These grades represent the tire's heat resistance when properly inflated and not overloaded. Sustained high temperature can cause the material of the tire to degenerate, reducing tire life and possibly leading to sudden catastrophic tire failure. According to NHTSA, the majority of tires rate B for temperature.

Traction is also rated with letter grades. A tire with a higher grade should allow a car to stop on a wet road in a shorter distance than a tire with a lower grade. Grades are AA (highest), A, B and C (lowest). The traction grade is based on braking straight ahead and does not include cornering or turning traction. Currently 3% of tires are rated AA; most are A-rated.

Treadwear is graded in comparison to a hypothetical control tire that is assigned a grade of 100. The treadwear grade indicates the expected life of a tire in comparison to the control tire. A tire with a grade of 200 would be expected to last twice as long as the control tire. However, it is important to remember that the relative life of tires depends on the actual conditions of their use, including driving habits, service practices and differences in road characteristics and climate.