Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder
and maximum section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration (NHTSA), which
grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use
spare tires, tires with nominal rim diameters
of 10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements and additional
General Motors Tire Performance Criteria (TPC)
standards.
Treadwear
The treadwear grade is a comparative rating based
on the wear rate of the tire when tested under
controlled conditions on a speci ed government
test course. For example, a tire graded 150 would
wear one and a half (1.5) times as well on the
government course as a tire graded 100. The
relative performance of tires depends upon the
actual conditions of their use, however, and may
depart signi cantly from the norm due to variations
in driving habits, service practices, and differences
in road characteristics and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, are AA,
A, B, and C. Those grades represent the tire’s
ability to stop on wet pavement as measured under
controlled conditions on speci ed government test
surfaces of asphalt and concrete. A tire marked C
may have poor traction performance.
Warning
:The traction grade assigned to
this tire is based on straight-ahead braking
traction tests, and does not include
acceleration, cornering, hydroplaning,
or peak traction characteristics.
5-70
Temperature – A, B, C
The temperature grades are A (the highest), B,
and C, representing the tire’s resistance to the
generation of heat and its ability to dissipate heat
when tested under controlled conditions on a
speci ed indoor laboratory test wheel. Sustained
high temperature can cause the material of the tire
to degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. The
grade C corresponds to a level of performance
which all passenger car tires must meet under the
Federal Motor Vehicle Safety Standard No. 109.
Grades B and A represent higher levels of
performance on the laboratory test wheel
than the minimum required by law.
Warning
:The temperature grade for this
tire is established for a tire that is properly
in ated and not overloaded. Excessive speed,
underin ation, or excessive loading, either
separately or in combination, can cause heat
buildup and possible tire failure.
Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be necessary
on a regular basis. However, if you notice unusual tire
wear or your vehicle pulling to one side or the other, the
alignment might need to be checked. If you notice your
vehicle vibrating when driving on a smooth road, the tires
and wheels might need to be rebalanced. See your
dealer/retailer for proper diagnosis.
5-71
If a Tire Goes Flat
Your vehicle has a tire sealant and compressor kit.
SeeTire Sealant and Compressor Kit on page 5-76.
There is no spare tire, no tire changing equipment,
and no place to store a tire.
It is unusual for a tire to blow out while you are driving,
especially if you maintain your tires properly. SeeTires
on page 5-51. If air goes out of a tire, it is much more
likely to leak out slowly. But, if you should ever have a
blow out, here are a few tips about what to expect and
what to do:
If a front tire fails, the at tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel rmly.
Steer to maintain lane position, and then gently brake
to a stop well out of the traffic lane.
A rear blow out, particularly on a curve, acts much
like a skid and may require the same correction
you would use in a skid. In any rear blow out, remove
your foot from the accelerator pedal. Get the vehicle
under control by steering the way you want the vehicle
to go. It may be very bumpy and noisy, but you can
still steer. Gently brake to a stop, well off the road
if possible.If a tire goes at, avoid further tire and wheel damage
by driving slowly to a level place and stopping.
Then do this:
1. Turn on the hazard warning ashers. SeeHazard
Warning Flashers on page 3-6.
2. Park your vehicle. If your vehicle has an automatic
transmission, set the parking brake rmly and put the
shift lever in PARK (P). SeeShifting Into PARK (P)
(Automatic Transmission) on page 2-26. If your
vehicle has a manual transmission, move the shift
lever to REVERSE (R) and set the parking brake
rmly. SeeParking Your Vehicle (Manual
Transmission) on page 2-28for additional
information.
3. Turn off the engine.
4. Inspect the at tire.
If the tire has been separated from the wheel, has
damaged sidewalls, or has a puncture larger than a
1 4inch (6 mm), the tire is too severely damaged for
the tire sealant and compressor kit to be effective.
SeeRoadside Assistance Program on page 7-7.
If the tire has a puncture less than a
1 4inch (6 mm)
in the tread area of the tire, seeTire Sealant and
Compressor Kit on page 5-76.
5-75
Scheduled Maintenance
When the CHANGE OIL SOON message on the Driver
Information Center (DIC) comes on, it means that
service is required for your vehicle. SeeDIC Warnings
and Messages on page 3-40. Have your vehicle
serviced as soon as possible within the next
600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the engine oil life
system may not indicate that vehicle service is necessary
for over a year. However, the engine oil and lter must be
changed at least once a year and at this time the system
must be reset. Your dealer/retailer has trained service
technicians who will perform this work using genuine
parts and reset the system.
If the engine oil life system is ever reset accidentally,
you must service your vehicle within 3,000 miles
(5 000 km) since your last service. Remember to reset
the oil life system whenever the oil is changed. See
Engine Oil Life System on page 5-19for information on
the Engine Oil Life System and resetting the system.When the CHANGE OIL SOON message appears,
certain services, checks, and inspections are required.
Required services are described in the following for
“MaintenanceI” and “MaintenanceII.” Generally,
it is recommended that your rst service be
MaintenanceI, your second service be MaintenanceII,
and that you alternate MaintenanceIand MaintenanceII
thereafter. However, in some cases, MaintenanceII
may be required more often.
MaintenanceI— Use MaintenanceIif the CHANGE
OIL SOON message comes on within 10 months
since the vehicle was purchased or MaintenanceIIwas
performed.
MaintenanceII— Use MaintenanceIIif the previous
service performed was MaintenanceI. Always use
MaintenanceIIwhenever the CHANGE OIL SOON
message comes on 10 months or more since the last
service or if the message has not come on at all
for one year.
6-4