OnStar Overview
EmergencyTire 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: The combined weight of optional accessories. Some examples
of optional accessories are automatic t ...
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. ...
Accessories and Modifications
Adding non-dealer accessories or making modifications to the vehicle can affect
vehicle performance and safety, including such things as airbags, braking, stability,
ride and handling, emissions systems, aerodynamics, durability, and electronic systems
like antilock brakes, traction control, a ...