(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The
letter “R” means radial ply construction; the letter “D”
means diagonal or bias ply construction; and the
letter “B” means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire.
The load index can range from 1 to 279. Speed ratings
range from A to Z.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to
its width.
Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.Bead:The tire bead contains steel wires wrapped by
steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold In ation Pressure:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat from
driving. SeeIn ation - Tire Pressure on page 5-56.
Curb Weight:This means the weight of a motor vehicle
with standard and optional equipment including the
maximum capacity of fuel, oil and coolant, but without
passengers and cargo.
DOT Markings:A code molded into the sidewall of a
tire signifying that the tire is in compliance with the
U.S. Department of Transportation motor vehicle safety
standards. The DOT code includes the Tire Identi cation
Number (TIN), an alphanumeric designator which can
also identify the tire manufacturer, production plant,
brand and date of production.
GVWR:Gross Vehicle Weight Rating, seeLoading
Your Vehicle on page 4-31.
GAWR FRT:Gross Axle Weight Rating for the front
axle, seeLoading Your Vehicle on page 4-31.
5-54
If a Tire Goes Flat
Your vehicle has no spare tire, no tire changing
equipment and no place to store a tire.
It’s unusual for a tire to “blow out” while you’re driving,
especially if you maintain your tires properly. See
Tires on page 5-51. If air goes out of a tire, it’s 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’d
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.
2. Set the parking brake rmly.
3. Put the shift lever in PARK (P).4. Turn off the engine.
5. Inspect the at tire.
If the tire has been separated from the wheel or has
damaged sidewalls or large tears that allow rapid
air loss, call a tire repair facility. SeeRoadside
Assistance Program on page 7-5.
If the at tire is due to a slow leak caused by a nail or
other similar road hazard, the tire in ator kit may be used
to repair the damaged tire temporarily. The kit uses a
liquid tire sealant to seal small punctures in the tread
area of the tire. The at tire is then in ated to at least
26 psi (179 kPa) and driven to evenly distribute the tire
sealant. The tire pressure is checked after driving for a
maximum of 10 minutes to see if the slow leak has been
stopped. If the tire pressure is 19 psi (131 kPa) or more,
in ate the tire up to the standard operating pressure as
shown on the tire and loading information label found on
center pillar near the door latch or on the rear edge of the
driver’s door. SeeIn ation - Tire Pressure on page 5-56.
You should have the damaged tire repaired as soon as
possible. The tire sealant is a temporary repair only.
For more information regarding the tire in ator kit
seeTire In ator Kit on page 5-66.
Notice:If the tire pressure has dropped below
19 psi (131 kPa), the vehicle should not be driven.
Damage to the tire may be severe and the sealant
will not be effective. Contact Roadside Assistance,
seeRoadside Assistance Program on page 7-5.
5-65