1993 GMC SIERRA wheel size

Problenrs on the Road
Jack Storage
Your jack and wheel ratchet are behind the passenger seat. Turn. th\
e wing
nut counterclockwise and remove the cover
if there is one.
Spare Tire
-
i
K2517
Your spare tire is either underneath the rear of the vehicle, or mounted to the
inside of the bed on the driver’s side.
If you have a chassis cab, refer to the
information from the body supplier/installer.
The spare tire
is a full size tire, like the other tires’ on your vehicle.
5-20
ProCarManuals.com

Dual Tire Rotation
K2659
Use one of these patterns if you have the same tire sizes and load ranges
on the front and rear.
K2660
1
Use this pattern if your front and rear tires are different sizes or load ranges.
When you install dual wheels, be sure the vent holes in the wheels are
lined up.
6-79
ProCarManuals.com

Service & Appearance Cam
When It’s Time for New Tires
K1656
One way to tell when it’s time for new tires is to check the treadwear
indicators, which will appear when your tires have only
2/32 inch (1.6 mm) or
less of tread remaining.
You need a new tire
if:
You can see the indicators at three places around the tire.
You can see cord or fabric 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 bump, bulge or split.
The tire has a puncture, cut, or other damage that can’t be repalred well
because of the size or location of the damage.
Dual Tire Operation
If your vehicle has dual rear wheels, the outer tire will usually\
wear faster
than the inner tire. Your tires will wear more evenly and last longer
if you
rotate the tires periodically.
If you’re going to be doing a lot of driving on
high-crown roads, you can reduce tire wear by adding
5 psi (35 kPa) to the
tire pressure in the outer tires. Be sure to return
to the recommended
pressures when no longer driving under those conditions.
6-80
ProCarManuals.com

r CAUTION I
If you operate your vehicle with a tire that is badly underinflated, the
tire can overheat. An overheated tire can lose air suddenly or catcl.
fire. You or others could be injured. Be sure all tires (including the
spare,
if any) are properly inflated.
Buying New Tires
To find out what kind and size of tires you need, look at the Certificationflire
label. The tires installed on your vehicle when it was new had a Tire
Performance Criteria Specification (TPC Spec) number on each tire’s sidewall.
When you get new tires, get ones with that same TPC Spec num\
ber. That
way, your vehicle will continue to have tires that are designed to give proper
endurance, handling, speed rating, traction, ride and other thin\
gs during
normal service on your vehicle. If your tires have an all-season tread design,
the TPC number will be followed by a
“MS” (for mud and snow).
If you ever replace your tires with those not having a TPC Spec number,
make sure they are the same size, load range, speed rating and construction
type (bias, bias-belted
or radial) as your original tires.
1 CAUTION
* Mixing tires could cause you to lose control while driving. If you mix
vehicle may not handle properly, and you could have a crash. Be
- ) tires of different sizes or types (radial and bias-belted tires), the
I sure to use the same size and type tires on all wheels. I
Uniform Tire Qua/ity Grading
The following information relates to the system developed by the United
States National Highway Traffic Safety Administration which grade\
s tires by
treadwear, traction and temperature performance. (This applies o\
nly to
vehicles sold in the United States.)
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the
tire when tested under controlled conditions on a specified governmen\
t test
course. For example, a tire graded
150 would wear one and a half (1 1/2)
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 significantly from the norm due to var\
iations in
driving habits, service practices and differences in road characteristics and
climate.
6-8 1
ProCarManuals.com

Service & Appearance Care
Tire Chains
If your vehicle has dual wheels or LT265175R16 size tires, don’t use tire
chains; they can damage your vehicle.
__ you don’t have dual wheels or if you have a tire size other than
LT265/75R16, use tire chains only when you must. Use only
SAE
“S” type chains that are the proper size for your tires. Install \
them on the
tires of the rear axle. 3
Tighten the as tightly as possible with the ends securely fastened. Drive I
slowly and TOIIOW the chain manufacturer’s instructions. If you can hear the
chains contacting your vehicle, stop and retighten them.
If the contact
continues, slow down until
it stops. Driving too fast with chains on will ’
nage your vehicle.
1 CAUTION
Appearance Cam
I
Cleaning products can be hazardous. Some are toxic. Others can \
L burst into flame if you strike a match or get them on a hot part of
the vehicle. Some are dangerous
if you breathe their fumes in a
zlosed space. When you use anything in a container to clean your
vehicle, be sure
to follow the instructions. And always open your
doors or windows when you’re cleaning the inside.
I ter use these to clean your vehicle:
Gasoline
Benzene
Naphtha
Carbon Tetrachloride
Acetone
Paint Thinner
Turpentine
Lacquer Thinner
Nail Polish Remover
They can all be hazardous-some more than others-and they can
all damage your vehicle, too.
6-84
ProCarManuals.com