Chevrolet 2010 Corvette Owner's Manual page 369

(F) Uniform Tire Quality Grading (UTQG)
Tire manufacturers are required to grade
tires based on three performance factors:
treadwear, traction and temperature resistance.
For more information see Uniform Tire Quality
Grading on page 6-82.
(G) Maximum Cold Inflation Load Limit
Maximum load that can be carried and the
maximum pressure needed to support that load.
Tire Size
The following illustration shows an example of a
typical passenger (p-metric) vehicle tire size.
(A) Passenger (P-Metric) Tire
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.
:
:
The United States
:
(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
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.
A letter code is used to
:
These characters
:
6-67