Cadillac 2010 DTS - Manual (Page 371)

(F) Tire Ply Material : The type of cord and
number of plies in the sidewall and under
the tread.
(G) Single Tire Maximum Load : Maximum load
that can be carried and the maximum pressure
needed to support that load when used as a
single. For information on recommended
tire pressure see Inflation - Tire Pressure on
page 6-54.
Tire Size
The following illustration shows an example of a
tire size.
(A) 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.
(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
60, as shown in item C of the illustration, it would
mean that the tire’s sidewall is 60 percent as
high as it is wide.
(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 : These characters
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.
6-51