GMC 2009 Sierra - Manual (Page 371)

CAUTION: (Continued)
• Overinflated tires are more likely to
be cut, punctured, or broken by a
sudden impact — such as when
you hit a pothole. Keep tires at the
recommended pressure.
• Worn, old tires can cause accidents.
If the tire’s tread is badly worn,
or if your vehicle’s tires have been
damaged, replace them.
20-Inch Tires
If your vehicle has the optional 20-inch
P275/55R20 size tires, they are classified as
touring tires and are designed for on road
use. The low-profile, wide tread design is not
recommended for off-road driving. See Off-Road
Driving on page 4-12, for additional information.
Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustrations are examples
of a typical P-Metric and a LT-Metric tire sidewall.
(A) Tire Size : The tire size code is a combination
of letters and numbers used to define a particular
tire’s width, height, aspect ratio, construction
type, and service description. See the “Tire Size”
illustration later in this section for more detail.
(B) TPC Spec (Tire Performance Criteria
Specification)
: Original equipment tires designed
to GM’s specific tire performance criteria have
a TPC specification code molded onto the sidewall.
GM’s TPC specifications meet or exceed all
federal safety guidelines.
Passenger (P-Metric) Tire
5-59