GMC 2008 Savana Van Owner's Manual page 311

GM's TPC Spec number is molded onto the tire's
sidewall near the tire size. If the tires have an all-season
tread design, the TPC spec number will be followed
by a MS, for mud and snow. See Tire Sidewall Labeling
on page 5-54 for additional information.
GM recommends replacing tires in sets of four (or six if
your vehicle has dual rear wheels). This is because
uniform tread depth on all tires will help keep your
vehicle performing most like it did when the tires were
new. Replacing less than a full set of tires can affect the
braking and handling performance of your vehicle. See
Tire Inspection and Rotation on page 5-68 for information
on proper tire rotation.
CAUTION:
{
Mixing tires could cause you to lose
control while driving. If you mix tires of
different sizes, brands, or types (radial
and bias-belted tires) the vehicle may not
handle properly, and you could have a
crash. Using tires of different sizes,
brands, or types may also cause damage to
your vehicle. Be sure to use the correct
size, brand, and type of tires on your
vehicle's wheels.
CAUTION:
{
If you use bias-ply tires on your vehicle,
the wheel rim flanges could develop
cracks after many miles of driving. A tire
and/or wheel could fail suddenly, causing
a crash. Use only radial-ply tires with the
wheels on your vehicle.
If you must replace your vehicle's tires with those that
do not have a TPC Spec number, make sure they are
the same size, load range, speed rating, and construction
type (radial and bias-belted tires) as your vehicle's
original tires.
Vehicles that have a tire pressure monitoring system
could give an inaccurate low-pressure warning if
non-TPC Spec rated tires are installed on your vehicle.
Non-TPC Spec rated tires may give a low-pressure
warning that is higher or lower than the proper warning
level you would get with TPC Spec rated tires.
See Tire Pressure Monitor System on page 5-62.
Your vehicle's original equipment tires are listed on the
Tire and Loading Information label. See Loading Your
Vehicle on page 4-20, for more information about the
Tire and Loading Information label and its location on
your vehicle.
5-71