Tire Myths

1.  I should inflate my tires according to the pressure indicated on the tire sidewall?

The tire's maximum inflation pressure not the recommended is molded on the sidewall. For normal operation, follow inflation pressure recommendations in the owner's manual or on the vehicle placard located in the glove box or on the door post. The function of air in a tire is to support the weight-carrying potential of a vehicle.  Thus, tires are built and rated to carry certain load capacities, and automakers select those sizes compatible with the ride, handling, traction, fuel economy and load requirements of their vehicles. Vehicle manufacturers determine inflation pressures based on these requirements.

A racing slick a tire without any tread provides the ultimate in dry traction due to the maximum amount of rubber touching the road. A tread pattern, with its groove voids, actually impairs this adhesion capability on dry roads. Tire tread acts as a squeegee on wet roads to remove water from under the tire and channel it through the grooves for improved wet traction.

3.  If not for the cost, race tires would be the ideal street tire for high-performance vehicles.

Race tires are engineered for specific track surfaces and race vehicle suspensions. On a high-performance vehicle, race tires would wear too quickly, provide an uncomfortable ride and deliver poor handling on wet or icy roadways. But in many cases, the technology used at the racetrack is engineered into high-performance street tires.

Performance tires may wear out faster than conventional family-car tires; however, tread rubber polymers aren't the culprits. In fact, new polymers and ultra-tensile steel constructions are making performance tires last longer than ever. Industry-wide, performance tires average about 45,000 miles in tread life, similar to the figures for family-car passenger tires. Fast wear usually is due to high-horsepower vehicles fitted with the tires and aggressive driving. Jackrabbit starts and quick stops can shorten the life of any tire.

5.  Wide tires provide better traction under all weather conditions.  In fact, putting oversized snow tires on a car delivers better snow traction.

In fact, the opposite is true. Wide tires tend to 'float' on deep snow and the tread lugs never have a chance to 'dig' through the snow to the road surface to gain traction. Narrow tires are a better option in deep snow. The tire acts similar to a knife cutting through butter; the blade works best when using the narrow edge to push through the butter rather than the wide flat side of the blade.

In some parts of the country this may be true, but if you live in the northern states or in Canada, the traction provided by winter tires can't be beat. Winter tires provide 25 percent improved traction in deep snow over all-season tires. Metal-studded tires deliver up to 40 percent greater traction on hard-packed snow and ice over all-seasons.

Radial tires can be crossed from side to side in the rotation pattern. The old front-to-back rule applied to bias ply tires. Regular tire rotation every 6,000 to 8,000 miles promotes more uniform wear for all tires on a vehicle.

8.  Sticking your fingernail in the tread can help pick the tire with the softest compounds, and thus, the best adhesion.

Tread compounds only tell part of a tire's story. Tread pattern, tire shape and the tire footprint shape on the pavement provide clues to its adhesion capabilities. Don't rely on the fingernail test.

9.  The government tests tires for traction, temperature resistance and treadwear and assigns grades that are molded onto the sidewall.

Uniform Tire Quality Grading is a federal law that requires tire manufacturers to grade their tires for treadwear, traction and temperature resistance. Tire manufacturers, not the government, test tires and assign their own grades. Unfortunately, the government has not prescribed a formula for converting the manufacturers test results into grades; therefore the numbers are not objective. According to the Federal Trade Commission, treadwear grades are for comparison purposes only and are not intended to be converted into anticipated or promised tire mileage.

Several polymers are used in a tire, depending on their performance characteristics. Run-flat tires, for example, use heat-dissipating polymer reinforcements that stiffen tire sidewalls, while tread compounds affect traction, treadwear, rolling resistance and noise.

Even premium tires can show signs of premature or uneven treadwear and imprecise steering when vehicles have defective alignment or suspension parts. Correct vehicle alignment is a must and should be checked periodically. Improper alignment causes excessive tire wear as well as increases fuel consumption. Regular tire rotation about every 6,000 to 8,000 miles promotes more uniform wear for all tires on a vehicle.

A tire engineered for low rolling resistance would provide horrible fuel economy when it is run under inflated. Running tires 20 percent under inflated by 6 to 7 pounds per square inch wastes fuel usage by as much as 10 percent. That amounts to Americans wasting nearly 4 million gallons of gasoline daily. Tire care is crucial in saving money at the pump.

13.  An undulation on a tire sidewall is a weak spot that could lead to tire failure.

An undulation is created where materials overlap each other in the tire carcass, and it actually is the strongest part of the tire. Still, motorists perceive a 'wave' on the sidewall as a defect. Goodyear's new ultra-tensile steel reinforcement eliminates this material splice and overlap. Ultra-tensile steel should reduce sidewall undulations found in polyester reinforced tires.

14.  Tires are a low-tech commodity, and price should determine what to buy.

Consider the rain, run-flat and performance tires on the market today. Time and technology have improved the quality and value of today's tires. Price should be only one consideration, along with the other factors that can enhance tire value and vehicle handling. For the industry, average passenger tire life has climbed from 24,000 miles in 1973 to about 47,000 miles today. No one would want to turn back the clock on tire developments or prices. On a cost-per-mile basis, tires from the so-called 'good old days' would cost more than three times that of a 65,000-mile name brand tire today.

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