General Motors
GM Communications
Detroit, Mich., USA
media.gm.com
For Release:
April 17, 2007
Goodwrench Says Proper Spring Tire Maintenance a Must
Tire Replacement: One Size Does Not Fit All
DETROIT – Road hazards and extreme temperatures can take a toll on vehicle tires over the harsh weather months. As
a driver’s ultimate connection to the road, tires need to be regularly inspected and properly maintained to preserve
their performance and handling characteristics. And, they should be replaced when necessary. This is where experts say
vehicle owners need to make well-informed choices.
According to the Car Care Council (www.carcare.org), during a recent National Car Care month 21 percent of the
vehicles inspected in check lanes had improperly inflated tires and 16 percent had worn tread and were in need of
replacement.
Tires fail for many reasons such as various road hazards, potholes, overloading, under-inflation, and wear out.
To size up the replacement issue, the Rubber Manufacturers Association reports that Americans discarded 300 million
tires and bought about 230 million passenger and light truck replacement tires in 2006.
“Consumers need to be choosy when purchasing new tires and replace them with the manufacturer’s specified tires for
their vehicle, because when it comes to tires, one size does not fit all,” said Dave Cowger, Engineering Group manager
of GM’s Tire–Wheel Systems Lab at the company’s Milford (Mich.) Proving Ground.
(MORE)
When it comes to designing, engineering and validating tire systems, GM follows an extremely rigorous and
comprehensive process. The GM Tire-Wheel Systems Laboratory puts tire-wheel assemblies through stringent tests to
ensure they meet or exceed internal, federal and Society of Automotive Engineers criteria.
GM’s tire and wheel engineers develop GM-exclusive Tire Performance Criteria (TPC) specifications for each vehicle
engineered in North America. TPC is industry-leading and ensures tire performance, handling and durability under a
2
variety of driving conditions. Major tire manufacturer engineers work together with GM’s tire and wheel engineers
during the validation process.
This GM advantage is carried into the marketplace. Only those select tires approved through the TPC process are
stamped with a TPC spec number, so customers can go to a GM dealership or a national tire brand retail store and
order a new tire that was specifically engineered to go with a specific GM vehicle.
“Tires are an engineering marvel, with 20 individual compounds and components designed to provide the customer
with an optimum blend of performance and durability,” said Cowger. “Replacing your tires with anything besides the
original equipment Tire Performance Criteria (TPC) specified tire can impact many safety and performance aspects of
a vehicle including braking, steering, cornering, ride and handling, noise and vibration, traction and even fuel
economy.”
Basic Tire Maintenance Tips
Some simple tire maintenance steps can help identify and address problems before replacement is needed, such as:

Check for uneven wear or excessive tread wear.

Make sure all tires, including the spare, are properly inflated. Inflate tires to recommended pressure. Underinflated tires can be a safety hazard, and according to the U.S. Department of Energy, can reduce fuel
economy by up to 3.3 percent.

Properly rotate tires at recommended intervals.

Properly align and balance wheels.
(MORE)
New Tires are Needed When
Tire wear depends on several factors, including driving style and tire maintenance habits. But one sure way to know
when to replace tires is when treadwear indicators appear. A tire’s built-in treadwear indicators are “wear bars” that
look like narrow strips of smooth rubber across the tread and appear when its time to replace the tire.
A new tire is needed if any of the following statements are true:

The indicators at three or more places around the tire are visible.

Cord or fabric is showing through the tire's rubber.

The tread or sidewall is cracked, cut or snagged deep enough to show cord or fabric.

The tire has a bulge or split.

The tire has a puncture, cut or other damage that can't be repaired well because of the size or location of the
damage.
3
Buying New Tires
To find out what kind and size of tires are needed, check the vehicle label. For GM vehicles engineered in North
America, the tires installed on each vehicle when it was new had a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When purchasing new tires, get ones with that same TPC Spec number. That way the
vehicle will continue to have tires that are designed to give proper endurance, handling, speed rating, traction, ride and
performance during normal service on the vehicle. If the tires have an all-season tread design, the TPC number will be
followed by an "M+S" (for mud and snow).
Each vehicle’s owner manual has more information on tires for that specific vehicle, or any Goodwrench dealer can
provide tire maintenance services and the correct TPC replacement tires.
(MORE)
About Goodwrench
Goodwrench is the service brand for GM vehicles - Chevrolet, Buick, Pontiac, GMC, HUMMER, and Cadillac. With
dealerships located nationwide and over 90,000 professionally trained service personnel, the Goodwrench network is
one of the largest automotive full-service providers in the industry. Goodwrench technicians receive specialized training
from General Motors to provide expert care for all GM cars and trucks. Goodwrench technicians readily use genuine
GM replacement parts, which are manufactured to the same specifications of the GM vehicle. For more information,
visit the GM Goodwrench web site at www.goodwrench.com.
###
Contacts:
Pamela Flores
SPO Communications
Pamela.flores@gm.com
810-606-3107
Eric Lingaur
Hass MS&L
Eric.lingaur@hassmsl.com
248-458-8649