Chevrolet Sonic Owner's Manual: Tire Designations
Tire Size
The following is an example of a typical passenger vehicle tire size.
(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 60, as shown in item 3 of the illustration, it would mean that the tire's sidewall is 60 percent as high as it is wide.
(4) 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.
(5) Rim Diameter: Diameter of the wheel in inches.
(6) Service Description: These 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.
Tire Sidewall Labeling
Useful information about a tire is molded into its sidewall. The examples show
a typical passenger vehicle tire and a compact spare tire sidewall.
Passenger (P-Metric) Tire Example
(1) Tire Size ...
Tire Terminology and Definitions
Air Pressure: The amount of air inside the tire pressing outward on each square
inch of the tire. Air pressure is expressed in kPa (kilopascal) or psi (pounds per
square inch).
Accessory Weight: ...
Other materials:
StabiliTrak® OFF Light
This light comes on briefly while starting the engine. If it does not, have the
vehicle serviced by your dealer.
This light comes on when the StabiliTrak system is turned off. If StabiliTrak
is off, the Traction Control System (TCS) is also off.
If the StabiliTrak and TCS are off, the system ...
SIR Identification Views
The SIR Identification Views shown below illustrate the approximate location
of all SIR components available for the vehicle. This will assist in determining
the appropriate SIR Disabling and Enabling for a given service procedure, refer
to SIR Disabling and Enabling.
Supplemental Inf ...
Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished, and
lapped surfaces with tolerances that are measured in ten thousandths of an inch.
When any internal engine parts are serviced, care and cleanliness are important.
A liberal coating of engine oil should be applied to fr ...
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