Chevrolet 2010 Express Owner's Manual page 334

(C) 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 C of the illustration, it would mean
that the tire's sidewall is 75 percent as high as it
is wide.
(D) Construction Code
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
represent the load index and speed rating of the
tire. The load index represents the load carry
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified
to carry a load.
6-64
A letter code is used to
:
These characters
:
Light Truck (LT-Metric) Tire
(A) Light Truck (LT-Metric) Tire
States version of a metric tire sizing system.
The letters LT as the first two characters in the
tire size means a light truck tire engineered
to standards set by the U.S. Tire and Rim
Association.
(B) Tire Width The three-digit number indicates
:
the tire section width in millimeters from sidewall
to sidewall.
(C) 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 C of the light truck (LT-Metric) tire
illustration, it would mean that the tire's sidewall is
75 percent as high as it is wide.
The United
: