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10-48
Vehicle Care
Tire Designations
Tire Size
The following examples show
the different parts of a tire size.
Passenger (P-Metric) Tire
(1) Passenger (P-Metric)
Tire
The United States version
:
of a metric tire sizing system.
The letter P as the first
character in the tire size means
a passenger vehicle tire
engineered to standards set by
the U.S. Tire and Rim
Association.
(2) Tire Width
The three-digit
:
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(3) Aspect Ratio
A two-digit
:
number that indicates the tire
height-to-width measurements.
For example, if the tire size
aspect ratio is 75, as shown in
item 3 of the illustration, it would
mean that the tire's sidewall is
75 percent as high as it is wide.
(4) Construction Code
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.
(5) Rim Diameter
Diameter of
:
the wheel in inches.
(6) Service Description
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
is certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.
A letter
:
Light Truck (LT-Metric) Tire
(1) Light Truck (LT-Metric)
Tire
The United States version
:
of a metric tire sizing system.
The letters LT as the first two
characters in the tire size mean
a light truck tire engineered to
standards set by the U.S. Tire
and Rim Association.
(2) Tire Width
number indicates the tire section
These
:
width in millimeters from
sidewall to sidewall.
(3) Aspect Ratio
number that indicates the tire
height-to-width measurements.
The three-digit
:
A two-digit
:
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