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
Tire Terminology and DefinitionsHands-Free Phone
General Information without Touchscreen
To use the hands-free phone on vehicles
without a touchscreen radio, press ,
select Onstar Hands-Free Calling, then enter the desired number.
General Information with Touchscreen
Vehicles with a Hands-Free Phone system can use a Bluetooth-capable cell p ...
Older Children
Older children who have outgrown booster seats should wear the vehicle safety
belts.
The manufacturer instructions that come with the booster seat state the weight
and height limitations for that booster. Use a booster seat with a lap-shoulder
belt until the child passes the fit test belo ...
Using the Tire Sealant and Compressor Kit to Temporarily Seal and Inflate a
Punctured Tire
When using the tire sealant and compressor kit during cold temperatures, warm
the kit in a heated environment for five minutes.
This will help to inflate the tire faster.
If a tire goes flat, avoid further tire and wheel damage by driving slowly to
a level place. Turn on the hazard warning fla ...